FCM - Not registered

Question

I\'m trying to send a message through FCM to my web app. Unfortunately, I\'ve the following error message and I\'m unable to solve it alone...

Through POSTMAN I rece

Answer 1

The official firebase documentation says:

An existing registration token may cease to be valid in a number of scenarios, including:

• If the client app unregisters with FCM.
• If the client app is automatically unregistered, which can happen if the user uninstalls the application. For example, on iOS, if the APNS Feedback Service reported the APNS token as invalid.
• If the registration token expires (for example, Google might decide to refresh registration tokens, or the APNS token has expired for iOS devices).
• If the client app is updated but the new version is not configured to receive messages.

For all these cases, remove this registration token from the app server and stop using it to send messages.

Usually you will receive this error in case when backend application sends a push with an expired token.