Creating and configuring a mobile app with FlutterFlow and Firebase can be a real challenge, especially when it comes to migrating your app to a different Firebase server or resolving issues with sending push notifications. This article will cover the key steps to successfully tackle these tasks.

### Migrating Your App to a Different Firebase Server

Checking SHA-1 and SHA-256 Signatures

The first step is to ensure that the SHA-1 and SHA-256 signatures match between Google Play and Firebase. During the automatic configuration of Firebase through FlutterFlow, these signatures may be altered, so it's crucial to download the original files from Firebase before deployment and verify that the SHA-1 and SHA-256 signatures are correct.

Server Location Matching

The second important aspect is to check the server location. If you've selected a server in Europe (e.g., \"europe-west1\"), make sure the same server location is set in FlutterFlow. Discrepancies in server location can lead to unexpected issues.

### Resolving Push Notification Issues

Checking FCM API Settings in Google Cloud Console

The third step involves checking the settings of the Firebase Cloud Messaging (FCM) API in the Google Cloud Console. It's essential to ensure that the FCM API is enabled and has a secret key displayed in the Firebase Console. If the key is not shown, you'll need to create a new key in the Google Cloud Console.

Removing Automatically Created Functions in Firebase

Before finalizing the push notification setup, delete all functions created by FlutterFlow in Firebase. Return to FlutterFlow, enable push notification settings, and proceed with the deployment, making sure the server location is correctly configured.

### Important Reminders

- Do not reconfigure the Firebase file, as this may lead to the addition of new SHA-1 and SHA-256 keys to your app in Firebase.

- Ensure you have assigned the correct roles to firebase@flutterflow.io (Service Account User, Editor, Cloud Function Admin).

After following these steps, which personally took me about a month, I was able to successfully release the updated app. Approximately 12 hours after deployment, push notifications began to arrive, and FCM tokens started being added to the user collection in Firebase. If you do not see the fcm_tokens subcollection, try logging out and logging back in to create it.

I hope this information proves helpful to you. If you have any further questions or need consultations, I am happy to support you. Please write to me at service@vr-group.io.

### Conclusion

Successfully migrating your app to a different Firebase server and resolving push notification issues requires attention to detail and adherence to specific procedures. By following these steps, you can minimize risks and ensure the stable operation of your app.

Push notification => Push notification sent to 0 devices