Push-Notifications at Android app are deactivated on account setup

When connecting to the server (NC 17.0.2, Talk 7.0.2) with the android app (Version 7.0.8), a short information “Push-Notification deactivated” is shown on the setup of a new account.

Using the iOS-app for the same server, push notification works as expected.

Does anyone know if I need some further configuration to activate push notification or to prevent it from being deactivated on account setup?

If you need further information from my side, please let me know.