Same issue here (with US sandbox account). I am totally new to both Clover and Android programming so I may be doing something wrong. But in any case "500 - internal server error" is not helpful. I am using Android Studio 3 and I tried both, creating a "Hello World" type of app from scratch as well as building an apk from one of the clover android-examples. I am probably using Gradle Plugin 3.0.0 (in my build.gradle I have classpath 'com.android.tools.build:gradle:3.0.0')
@Martins @alexb, there's a known issue when using gradle plugin version 3.0.0. The recommendation is to downgrade your gradle plugin to a version like 2.3.3. This should resolve the issue when uploading an APK.
Here are instructions on how to change the gradle plugin version: https://stackoverflow.com/questions/35425143/can-we-change-gradle-plugin-version-in-android-studio
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