Autocomplete is not working (browser chrome)

Question

I have a form login. Normaly, the chrome save the settings, and each time the user access to that form, the last input values are automatically insert. But in my form, the browser does not behaves like that.

[Edit] : This behavior it is just appending to chrome browser

Follows the HTML code:

<form action="#" class="ac-custom ac-checkbox ac-checkmark" onsubmit="UIAuthetication.prototype.ClickButtonSignedIn(true); return false;">
                            <div class="username line checkThisDiv">
                                <input class="input TR_Login_Username" type="text" required="" placeholder="E-mail" mandatory="" vk_15c42="subscribed">
                                <h6 class="TR_Login_Username">E-mail</h6>
                                <p class="error_message"></p>
                            </div>
                                                    <div class="password line checkThisDiv">
                                <input class="input TR_Login_Password" type="password" required="" placeholder="Password" mandatory="" vk_15c42="subscribed">
                                <h6 class="TR_Login_Password">Password</h6>
                                <p class="error_message"></p>
                            </div>

                            <div class="line line-submit">
                                <input class="submit right TR_Login_Button" type="submit" value="Login">
                                <ul>
                                    <li>
                                        <input class="keepSignIn remember" type="checkbox">
                                        <label class="TR_Login_Keep_Me_Signed_In" for="cb6">Remember user</label>
                                    <svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg"></svg></li>
                                </ul>
                            </div>


                    </form>

Answer 1

So, with the attempt-error method, I discovery if I put ID's to the inputs, the chrome autocomplete will work. I don't know the reason of that, I just know with that, the problem was solve.