Use this article when Firebase initialization or configuration fails. If the app runs normally but a message is not delivered, also follow Troubleshooting Push Notifications.
Check that lib/firebase_options.dart was generated for your Firebase project and intended platform. Verify the matching google-services.json or GoogleService-Info.plist and platform identifiers.
The app already initializes Firebase in lib/main.dart. Adding another unconditional initialization can create a second problem rather than resolving the original configuration error.
A “No matching client” error usually warrants comparing the built application ID with the Android app registration. Download configuration for the correct registration and perform a full rebuild.
Verify bundle identifiers, plist target membership, Apple signing, and APNs setup. A working Firebase core initialization does not by itself establish that push registration is ready.
If a direct Firebase test reaches the device but a CRM push fails, inspect the module’s Firebase project ID, server credential configuration, device registration, and selected audience. Keep server clock and outbound HTTPS connectivity in working order.
Record sanitized error messages and the stage that fails. Never share service-account JSON, APNs private keys, complete push tokens, or screenshots containing credentials. Reconfigure from the official Firebase console instead of editing credentials copied from another project.