Flutter APK release build fails to upload to Fabric Beta

Having this issue only with Flutter builds. I've tried uploading both with the Android Studio Fabric plugin, and with Fastlane command.

When attempting to upload using the Android Studio Fabric plugin drag & drop, an error displays showing: Unable to extract Crashlytics build info from the dropped APK. Please make sure your Crashlytics build tool plugin is installed and enabled.

When attempting to uploading using Fastlane with command: fastlane run crashlytics apk_path:"/home/me/app-release.apk" api_token:"xxx" build_secret:"xx"

This error comes up:

[17:26:01]: -------------------------
[17:26:01]: --- Step: crashlytics ---
[17:26:01]: -------------------------
[17:26:01]: Uploading the build to Crashlytics Beta. Time for some ☕️.
[17:26:02]: Shell command exited with exit status 1 instead of 0.

[!]  WARN - Crashlytics halted compilation because it can't extract Crashlytics build info from the APK: /home/me/app-release.apk
Exception in thread "main" com.crashlytics.tools.android.exception.PluginException: Distribution upload failed.
        at com.crashlytics.tools.android.DeveloperTools.processProperties(DeveloperTools.java:667)
        at com.crashlytics.tools.android.DeveloperTools.processArgsInternal(DeveloperTools.java:348)
        at com.crashlytics.tools.android.DeveloperTools.main(DeveloperTools.java:273)
Caused by: com.crashlytics.tools.android.exception.DistributionException: Crashlytics halted compilation because it can't extract Crashlytics build info from the APK: /home/me/app-release.apk
        at com.crashlytics.tools.android.DistributionTasks.uploadDistribution(DistributionTasks.java:64)
        at com.crashlytics.tools.android.DeveloperTools.processProperties(DeveloperTools.java:665)
        ... 2 more

Steps I have taken to implement crashlytics:

Added and set up firebase_crashlytics as a flutter dependency using instructions: https://pub.dev/packages/firebase_crashlytics
Added the Fabric API key to the AndroidManifest.xml
Upon running the app after set up, the app showed up in Fabric console, meaning Crashlytics is now set up fine.
Then attempted Fabric Beta upload using the APK generated from flutter build apk --release trying both the Android Studio plugin and Fastlane, resulting in the above errors.

Am I missing anything? Has anyone had success with uploading a Flutter build to Fabric Beta and somehow resolved the Crashlytics info missing error?

Upvotes: 1