Why are my Android push notifications not working after migrating to the new Firebase Cloud Messaging (FCM) API?

If you have recently moved your Android application to the Firebase Cloud Messaging HTTP v1 API and notifications have stopped working, the cause is usually a configuration mismatch. Check the following three things:

1. Upload your FCM service account key. In the Pushwoosh Control Panel go to Settings → Configure platforms, find the Android row and click Connect. Use IMPORT FCM SERVICE ACCOUNT KEY to upload the JSON private key generated in your Firebase project (Project settings → Service accounts → Generate new private key), then click Apply. The legacy FCM Server Key and Sender ID credentials were retired by Google in June 2024 and are no longer part of the Pushwoosh Android configuration — the service account JSON is the only supported credential.
2. Ensure project consistency. The google-services.json bundled with your Android app must come from the exact same Firebase project as the service account key you uploaded to Pushwoosh. Credentials from two different Firebase projects will cause delivery to fail.
3. Enable the FCM API. Verify that the Firebase Cloud Messaging API is enabled in Google Cloud Console for that project: https://console.cloud.google.com/apis/library/fcm.googleapis.com.

These three steps resolve the most common delivery issues after migrating to FCM v1. Always test on a real physical device rather than an emulator for accurate results.