swift4: none of textfields in my scene are editable

Question

I have a Scene in my Storyboard which all of its field are not editable during application run-time.

Note. I've checked that all text field and all its parent userInteractionEnabled be true and due to this question (My TextField is not editable) but it did not help. I have other scenes like this that work without using any delegates or such things and their textfields are still editable.

I did comment out everything inside its related view controller however it did not change this situation. I've brought its XML code here for your reference may be you can find anything which lead to this situation.

Changes which I made to my Scene was: Puting all items in a nested view inside a StackView and some if its constraints + migrating from Swift3 to Swift4.

<viewController storyboardIdentifier="CreateNewAddressViewController" id="meF-fr-sNf" customClass="CreateNewAddressViewController" customModule="nopStation" customModuleProvider="target" sceneMemberID="viewController">
    <view key="view" contentMode="scaleToFill" id="AwK-Dk-u5T">
        <rect key="frame" x="0.0" y="0.0" width="375" height="800"/>
        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
        <subviews>
            <scrollView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" ambiguous="YES" translatesAutoresizingMaskIntoConstraints="NO" id="FhN-qH-KZv">
                <rect key="frame" x="10" y="84" width="355" height="646"/>
                <subviews>
                    <view contentMode="scaleToFill" ambiguous="YES" translatesAutoresizingMaskIntoConstraints="NO" id="goD-MV-xj2">
                        <rect key="frame" x="0.0" y="0.0" width="355" height="590"/>
                        <subviews>
                            <stackView opaque="NO" contentMode="scaleToFill" fixedFrame="YES" axis="vertical" spacing="10" translatesAutoresizingMaskIntoConstraints="NO" id="o9G-FL-lqF">
                                <rect key="frame" x="10" y="0.0" width="335" height="290"/>
                                <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                <subviews>
                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="WMA-Km-72c">
                                        <rect key="frame" x="0.0" y="0.0" width="335" height="40"/>
                                        <subviews>
                                            <textField opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" placeholder="First Name" textAlignment="natural" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="fKn-8z-Pzc">
                                                <rect key="frame" x="0.0" y="0.0" width="316.5" height="40"/>
                                                <fontDescription key="fontDescription" type="system" pointSize="15"/>
                                                <textInputTraits key="textInputTraits"/>
                                            </textField>
                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="*" textAlignment="center" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="fUe-Bq-W8T">
                                                <rect key="frame" x="326.5" y="9.5" width="8.5" height="21.5"/>
                                                <fontDescription key="fontDescription" type="boldSystem" pointSize="18"/>
                                                <color key="textColor" name="RequiredFieldColor"/>
                                                <nil key="highlightedColor"/>
                                            </label>
                                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="dMl-Cd-fC6">
                                                <rect key="frame" x="0.0" y="38" width="335" height="2"/>
                                                <color key="backgroundColor" red="0.66666666669999997" green="0.66666666669999997" blue="0.66666666669999997" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                                <constraints>
                                                    <constraint firstAttribute="height" constant="2" id="Yrr-ai-qmM"/>
                                                </constraints>
                                            </view>
                                        </subviews>
                                        <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
                                        <constraints>
                                            <constraint firstItem="dMl-Cd-fC6" firstAttribute="leading" secondItem="WMA-Km-72c" secondAttribute="leading" id="4z7-jV-IUk"/>
                                            <constraint firstAttribute="bottom" secondItem="dMl-Cd-fC6" secondAttribute="bottom" id="F8F-RI-rg4"/>
                                            <constraint firstItem="fUe-Bq-W8T" firstAttribute="centerY" secondItem="WMA-Km-72c" secondAttribute="centerY" id="I89-Go-X44"/>
                                            <constraint firstAttribute="bottom" secondItem="fKn-8z-Pzc" secondAttribute="bottom" id="JTN-Ml-5Eo"/>
                                            <constraint firstItem="fUe-Bq-W8T" firstAttribute="leading" secondItem="fKn-8z-Pzc" secondAttribute="trailing" constant="10" id="RcN-3E-CP8"/>
                                            <constraint firstAttribute="trailing" secondItem="dMl-Cd-fC6" secondAttribute="trailing" id="X8s-r3-rol"/>
                                            <constraint firstItem="fKn-8z-Pzc" firstAttribute="top" secondItem="WMA-Km-72c" secondAttribute="top" id="bek-aj-mKk"/>
                                            <constraint firstItem="fKn-8z-Pzc" firstAttribute="leading" secondItem="WMA-Km-72c" secondAttribute="leading" id="ghL-fb-IFL"/>
                                            <constraint firstAttribute="trailing" secondItem="fUe-Bq-W8T" secondAttribute="trailing" id="tmI-VS-dyA"/>
                                            <constraint firstAttribute="height" constant="40" id="xLm-i2-YEp"/>
                                        </constraints>
                                    </view>
                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="P0X-pA-gjs">
                                        <rect key="frame" x="0.0" y="50" width="335" height="40"/>
                                        <subviews>
                                            <textField opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" placeholder="Last Name" textAlignment="natural" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="DfQ-XX-xII">
                                                <rect key="frame" x="0.0" y="0.0" width="316.5" height="40"/>
                                                <fontDescription key="fontDescription" type="system" pointSize="15"/>
                                                <textInputTraits key="textInputTraits"/>
                                            </textField>
                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="*" textAlignment="center" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="7TX-E6-XLu">
                                                <rect key="frame" x="326.5" y="9.5" width="8.5" height="21.5"/>
                                                <fontDescription key="fontDescription" type="boldSystem" pointSize="18"/>
                                                <color key="textColor" name="RequiredFieldColor"/>
                                                <nil key="highlightedColor"/>
                                            </label>
                                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="5hQ-6V-Wq0">
                                                <rect key="frame" x="0.0" y="38" width="335" height="2"/>
                                                <color key="backgroundColor" red="0.66666666669999997" green="0.66666666669999997" blue="0.66666666669999997" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                                <constraints>
                                                    <constraint firstAttribute="height" constant="2" id="FNO-9t-n52"/>
                                                </constraints>
                                            </view>
                                        </subviews>
                                        <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
                                        <constraints>
                                            <constraint firstItem="DfQ-XX-xII" firstAttribute="top" secondItem="P0X-pA-gjs" secondAttribute="top" id="0g2-tp-rW4"/>
                                            <constraint firstAttribute="trailing" secondItem="5hQ-6V-Wq0" secondAttribute="trailing" id="8eK-Vx-f2y"/>
                                            <constraint firstAttribute="bottom" secondItem="5hQ-6V-Wq0" secondAttribute="bottom" id="Fiu-Kw-SJQ"/>
                                            <constraint firstAttribute="bottom" secondItem="DfQ-XX-xII" secondAttribute="bottom" id="LqW-0G-dQv"/>
                                            <constraint firstItem="5hQ-6V-Wq0" firstAttribute="leading" secondItem="P0X-pA-gjs" secondAttribute="leading" id="RAi-YU-lOk"/>
                                            <constraint firstItem="DfQ-XX-xII" firstAttribute="leading" secondItem="P0X-pA-gjs" secondAttribute="leading" id="hQA-Cy-Icv"/>
                                            <constraint firstAttribute="height" constant="40" id="jpn-Ph-BBz"/>
                                            <constraint firstItem="7TX-E6-XLu" firstAttribute="centerY" secondItem="P0X-pA-gjs" secondAttribute="centerY" id="kXU-Bp-hcH"/>
                                            <constraint firstAttribute="trailing" secondItem="7TX-E6-XLu" secondAttribute="trailing" id="wc4-6s-KgF"/>
                                            <constraint firstItem="7TX-E6-XLu" firstAttribute="leading" secondItem="DfQ-XX-xII" secondAttribute="trailing" constant="10" id="zHs-Pr-2vS"/>
                                        </constraints>
                                    </view>
                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="Nnr-ax-dhk">
                                        <rect key="frame" x="0.0" y="100" width="335" height="40"/>
                                        <subviews>
                                            <textField opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" placeholder="Email" textAlignment="natural" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="BhZ-fY-4k7">
                                                <rect key="frame" x="0.0" y="0.0" width="316.5" height="40"/>
                                                <fontDescription key="fontDescription" type="system" pointSize="15"/>
                                                <textInputTraits key="textInputTraits"/>
                                            </textField>
                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="*" textAlignment="center" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="j0N-ZY-V0Y">
                                                <rect key="frame" x="326.5" y="9.5" width="8.5" height="21.5"/>
                                                <fontDescription key="fontDescription" type="boldSystem" pointSize="18"/>
                                                <color key="textColor" name="RequiredFieldColor"/>
                                                <nil key="highlightedColor"/>
                                            </label>
                                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="nTG-O0-l4y">
                                                <rect key="frame" x="0.0" y="38" width="335" height="2"/>
                                                <color key="backgroundColor" red="0.66666666669999997" green="0.66666666669999997" blue="0.66666666669999997" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                                <constraints>
                                                    <constraint firstAttribute="height" constant="2" id="u9W-Yq-hih"/>
                                                </constraints>
                                            </view>
                                        </subviews>
                                        <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
                                        <constraints>
                                            <constraint firstItem="BhZ-fY-4k7" firstAttribute="leading" secondItem="Nnr-ax-dhk" secondAttribute="leading" id="3hK-ug-6Ys"/>
                                            <constraint firstAttribute="trailing" secondItem="nTG-O0-l4y" secondAttribute="trailing" id="54C-vF-p3i"/>
                                            <constraint firstAttribute="bottom" secondItem="nTG-O0-l4y" secondAttribute="bottom" id="7ef-y6-enL"/>
                                            <constraint firstAttribute="trailing" secondItem="j0N-ZY-V0Y" secondAttribute="trailing" id="B5b-XV-RYP"/>
                                            <constraint firstItem="j0N-ZY-V0Y" firstAttribute="centerY" secondItem="Nnr-ax-dhk" secondAttribute="centerY" id="BUL-N2-cNw"/>
                                            <constraint firstItem="nTG-O0-l4y" firstAttribute="leading" secondItem="Nnr-ax-dhk" secondAttribute="leading" id="Nib-ZA-Ihq"/>
                                            <constraint firstItem="BhZ-fY-4k7" firstAttribute="top" secondItem="Nnr-ax-dhk" secondAttribute="top" id="Rey-qG-CSa"/>
                                            <constraint firstItem="j0N-ZY-V0Y" firstAttribute="leading" secondItem="BhZ-fY-4k7" secondAttribute="trailing" constant="10" id="dx4-BK-uWj"/>
                                            <constraint firstAttribute="bottom" secondItem="BhZ-fY-4k7" secondAttribute="bottom" id="p5m-SO-CZ7"/>
                                            <constraint firstAttribute="height" constant="40" id="wBB-11-ud1"/>
                                        </constraints>
                                    </view>
                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="m6n-mP-IDR">
                                        <rect key="frame" x="0.0" y="150" width="335" height="40"/>
                                        <subviews>
                                            <textField opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" placeholder="Address 1" textAlignment="natural" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="9Xe-87-5pU">
                                                <rect key="frame" x="0.0" y="0.0" width="316.5" height="38"/>
                                                <fontDescription key="fontDescription" type="system" pointSize="15"/>
                                                <textInputTraits key="textInputTraits"/>
                                            </textField>
                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="*" textAlignment="center" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="cLO-wm-dKq">
                                                <rect key="frame" x="326.5" y="9.5" width="8.5" height="21.5"/>
                                                <fontDescription key="fontDescription" type="boldSystem" pointSize="18"/>
                                                <color key="textColor" name="RequiredFieldColor"/>
                                                <nil key="highlightedColor"/>
                                            </label>
                                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="0v1-IU-zJP">
                                                <rect key="frame" x="0.0" y="38" width="335" height="2"/>
                                                <color key="backgroundColor" red="0.66666666669999997" green="0.66666666669999997" blue="0.66666666669999997" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                                <constraints>
                                                    <constraint firstAttribute="height" constant="2" id="xj6-r6-dVL"/>
                                                </constraints>
                                            </view>
                                        </subviews>
                                        <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
                                        <constraints>
                                            <constraint firstAttribute="trailing" secondItem="0v1-IU-zJP" secondAttribute="trailing" id="7ol-EC-Z7f"/>
                                            <constraint firstItem="0v1-IU-zJP" firstAttribute="top" secondItem="9Xe-87-5pU" secondAttribute="bottom" id="9Kh-vz-aHF"/>
                                            <constraint firstItem="cLO-wm-dKq" firstAttribute="leading" secondItem="9Xe-87-5pU" secondAttribute="trailing" constant="10" id="BzA-q4-AUa"/>
                                            <constraint firstItem="cLO-wm-dKq" firstAttribute="centerY" secondItem="m6n-mP-IDR" secondAttribute="centerY" id="DLF-Sg-4fb"/>
                                            <constraint firstAttribute="trailing" secondItem="cLO-wm-dKq" secondAttribute="trailing" id="Ddh-gm-hyM"/>
                                            <constraint firstItem="9Xe-87-5pU" firstAttribute="top" secondItem="m6n-mP-IDR" secondAttribute="top" id="V6F-fl-0nK"/>
                                            <constraint firstItem="0v1-IU-zJP" firstAttribute="leading" secondItem="m6n-mP-IDR" secondAttribute="leading" id="cly-NY-H6S"/>
                                            <constraint firstItem="9Xe-87-5pU" firstAttribute="leading" secondItem="m6n-mP-IDR" secondAttribute="leading" id="mCt-JT-svl"/>
                                            <constraint firstAttribute="height" constant="40" id="sGm-DQ-Zyt"/>
                                            <constraint firstAttribute="bottom" secondItem="0v1-IU-zJP" secondAttribute="bottom" id="uXh-8G-dAn"/>
                                        </constraints>
                                    </view>

                                        <rect key="frame" x="0.0" y="250" width="335" height="40"/>
                                        <subviews>
                                            <textField opaque="NO" clipsSubviews="YES" contentMode="scaleToFill" contentHorizontalAlignment="left" contentVerticalAlignment="center" placeholder="Phone Number" textAlignment="natural" minimumFontSize="17" translatesAutoresizingMaskIntoConstraints="NO" id="ykM-gm-kv4">
                                                <rect key="frame" x="0.0" y="0.0" width="316.5" height="40"/>
                                                <fontDescription key="fontDescription" type="system" pointSize="15"/>
                                                <textInputTraits key="textInputTraits"/>
                                            </textField>
                                            <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="*" textAlignment="center" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="l86-0I-WbN">
                                                <rect key="frame" x="326.5" y="9.5" width="8.5" height="21.5"/>
                                                <fontDescription key="fontDescription" type="boldSystem" pointSize="18"/>
                                                <color key="textColor" name="RequiredFieldColor"/>
                                                <nil key="highlightedColor"/>
                                            </label>
                                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="b1z-D7-bNt">
                                                <rect key="frame" x="0.0" y="38" width="335" height="2"/>
                                                <color key="backgroundColor" red="0.66666666669999997" green="0.66666666669999997" blue="0.66666666669999997" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                                <constraints>
                                                    <constraint firstAttribute="height" constant="2" id="4ev-LH-vny"/>
                                                </constraints>
                                            </view>
                                        </subviews>
                                        <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
                                        <constraints>
                                            <constraint firstItem="l86-0I-WbN" firstAttribute="leading" secondItem="ykM-gm-kv4" secondAttribute="trailing" constant="10" id="6qg-ch-5Kj"/>
                                            <constraint firstItem="ykM-gm-kv4" firstAttribute="top" secondItem="FsO-iO-UA3" secondAttribute="top" id="81o-ef-AGF"/>
                                            <constraint firstAttribute="height" constant="40" id="9mW-zj-58j"/>
                                            <constraint firstItem="ykM-gm-kv4" firstAttribute="centerY" secondItem="FsO-iO-UA3" secondAttribute="centerY" id="Amc-P7-79p"/>
                                            <constraint firstAttribute="bottom" secondItem="b1z-D7-bNt" secondAttribute="bottom" id="HBK-sg-EAD"/>
                                            <constraint firstItem="ykM-gm-kv4" firstAttribute="leading" secondItem="FsO-iO-UA3" secondAttribute="leading" id="RcY-bk-6yR"/>
                                            <constraint firstAttribute="trailing" secondItem="b1z-D7-bNt" secondAttribute="trailing" id="W2P-F3-Hlg"/>
                                            <constraint firstAttribute="trailing" secondItem="l86-0I-WbN" secondAttribute="trailing" id="efh-fE-eln"/>
                                            <constraint firstItem="l86-0I-WbN" firstAttribute="centerY" secondItem="FsO-iO-UA3" secondAttribute="centerY" id="hgs-xM-U20"/>
                                            <constraint firstItem="b1z-D7-bNt" firstAttribute="leading" secondItem="FsO-iO-UA3" secondAttribute="leading" id="qLG-Sc-NEU"/>
                                            <constraint firstAttribute="bottom" secondItem="ykM-gm-kv4" secondAttribute="bottom" id="yg9-Kg-K83"/>
                                        </constraints>
                                    </view>
                                </subviews>
                            </stackView>
                        </subviews>
                        <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
                    </view>
                </subviews>
                <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                <constraints>
                    <constraint firstAttribute="trailing" secondItem="goD-MV-xj2" secondAttribute="trailing" id="Dak-14-pgV"/>
                    <constraint firstAttribute="bottom" secondItem="goD-MV-xj2" secondAttribute="bottom" id="Eve-uT-c8i"/>
                    <constraint firstItem="goD-MV-xj2" firstAttribute="leading" secondItem="FhN-qH-KZv" secondAttribute="leading" id="HWd-e0-G4Q"/>
                    <constraint firstItem="goD-MV-xj2" firstAttribute="top" secondItem="FhN-qH-KZv" secondAttribute="top" id="ln7-n8-Afi"/>
                </constraints>
                <userDefinedRuntimeAttributes>
                    <userDefinedRuntimeAttribute type="number" keyPath="layer.cornerRadius">
                        <integer key="value" value="4"/>
                    </userDefinedRuntimeAttribute>
                </userDefinedRuntimeAttributes>
            </scrollView>
            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="4cS-bG-FbJ">
                <rect key="frame" x="10" y="734" width="355" height="40"/>
                <color key="backgroundColor" name="AccentColor"/>
                <constraints>
                    <constraint firstAttribute="height" constant="40" id="MoG-YS-fiL"/>
                </constraints>
                <fontDescription key="fontDescription" type="boldSystem" pointSize="15"/>
                <state key="normal" title="SAVE">
                    <color key="titleColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                </state>
                <userDefinedRuntimeAttributes>
                    <userDefinedRuntimeAttribute type="number" keyPath="layer.cornerRadius">
                        <integer key="value" value="4"/>
                    </userDefinedRuntimeAttribute>
                </userDefinedRuntimeAttributes>
                <connections>
                    <action selector="saveBtnAct:" destination="meF-fr-sNf" eventType="touchUpInside" id="3cT-XX-k4z"/>
                </connections>
            </button>
        </subviews>
        <color key="backgroundColor" red="0.8862745098" green="0.8862745098" blue="0.8862745098" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
        <constraints>
            <constraint firstItem="gQb-mV-QRj" firstAttribute="trailing" secondItem="FhN-qH-KZv" secondAttribute="trailing" constant="10" id="Ke5-D5-K26"/>
            <constraint firstItem="4cS-bG-FbJ" firstAttribute="leading" secondItem="gQb-mV-QRj" secondAttribute="leading" constant="10" id="Tk0-nE-xox"/>
            <constraint firstItem="gQb-mV-QRj" firstAttribute="bottom" secondItem="4cS-bG-FbJ" secondAttribute="bottom" constant="26" id="Zor-Jg-W1u"/>
            <constraint firstItem="4cS-bG-FbJ" firstAttribute="top" secondItem="FhN-qH-KZv" secondAttribute="bottom" constant="4" id="clQ-NQ-TBp"/>
            <constraint firstItem="goD-MV-xj2" firstAttribute="width" secondItem="AwK-Dk-u5T" secondAttribute="width" constant="-20" id="h9X-0l-yIk"/>
            <constraint firstItem="FhN-qH-KZv" firstAttribute="top" secondItem="gQb-mV-QRj" secondAttribute="top" constant="64" id="i2a-Mw-TF0"/>
            <constraint firstItem="FhN-qH-KZv" firstAttribute="leading" secondItem="gQb-mV-QRj" secondAttribute="leading" constant="10" id="qEg-VO-wiQ"/>
            <constraint firstItem="gQb-mV-QRj" firstAttribute="trailing" secondItem="4cS-bG-FbJ" secondAttribute="trailing" constant="10" id="u44-kZ-irC"/>
        </constraints>
        <viewLayoutGuide key="safeArea" id="gQb-mV-QRj"/>
    </view>
    <freeformSimulatedSizeMetrics key="simulatedDestinationMetrics"/>
    <size key="freeformSize" width="375" height="800"/>
    <connections>
        <outlet property="address1RequiredLabel" destination="cLO-wm-dKq" id="4ze-PL-To9"/>
        <outlet property="address1TextField" destination="9Xe-87-5pU" id="uMF-aw-PQZ"/>
        <outlet property="address2RequiredLabel" destination="Bnx-Sa-95p" id="882-gU-i1B"/>
        <outlet property="address2TextField" destination="zB0-7l-zSy" id="OCL-Wg-V3e"/>
        <outlet property="containerScrollView" destination="FhN-qH-KZv" id="Qgr-4M-3ah"/>
        <outlet property="emailRequiredLabel" destination="j0N-ZY-V0Y" id="H2q-yS-KW4"/>
        <outlet property="emailTextField" destination="BhZ-fY-4k7" id="ctw-kQ-7hc"/>
        <outlet property="firstNameRequiredLabel" destination="fUe-Bq-W8T" id="Pp0-BF-EIE"/>
        <outlet property="firstNameTextField" destination="fKn-8z-Pzc" id="CgT-Uw-Ixy"/>
        <outlet property="lastNameRequiredLabel" destination="7TX-E6-XLu" id="gap-4c-FWJ"/>
        <outlet property="lastNameTextField" destination="DfQ-XX-xII" id="H92-Zq-2u2"/>
        <outlet property="phoneNumberRequiredTextField" destination="l86-0I-WbN" id="CGi-on-wOu"/>
        <outlet property="phoneNumberTextField" destination="ykM-gm-kv4" id="MbB-FK-z0c"/>
        <outlet property="saveBtn" destination="4cS-bG-FbJ" id="XPF-Hi-Xtb"/>
        <outlet property="saveBtnBottomConstant" destination="Zor-Jg-W1u" id="UJd-is-ceY"/>
    </connections>
</viewController>
<placeholder placeholderIdentifier="IBFirstResponder" id="ssH-lW-xhj" userLabel="First Responder" sceneMemberID="firstResponder"/>

Answer 1

I have pasted your storyboard in my Test project and tried debugging this issue. It is found that when the view between ScrollView and StackView ( highlighted in RED in below screenshot) is removed and StackView is directly placed inside Container ScrollView, the textFields become clickable.

Your storyboard as given:

After removing view inside Container Scroll view and moving StackView directly under Container ScrollView.

Simulator screenshot after removing that middle view