CODEWITHSUNDEEP
androidfirebasegoogle-cloud-messagingfirebase-cloud-messaging
kencorbin
kencorbin

Reputation: 2008

Upgrading GCM to FCM server reports MismatchSenderId error

My current production app uses and older version of GCM. The instructions on how to upgrade GCM to FCM did not quite fit in a couple places, but I have mostly completed the migration, and it almost works.

I can send messages from the developer console to the new FCM version of the app. OK, so far...

After changing the backend server endpoint to fcm.googleapis.com/fcm/ the server can continue to send messages to the old GCM versions of my app. Just like it used to do.

But when the backend server attempts to send a message to the new FCM version of the app, the request is rejected with a MismatchSenderId error. We are using the same sender ID that works perfectly with the GCM versions of the app. Everyone is using the same project. Is there something I have to do to import the old GCM project settings? If I change the backend server to use the new FCM server keys, will it still be able to push messages to the old GCM versions of the app?

Upvotes: 3

Views: 349

Answers (2)

kencorbin
kencorbin

Reputation: 2008

Google support eventually responded and help track this down. It turns out that I had accidentally, and unknowingly, created a second FCM project with another sender ID. And had registered the app with the wrong project.

Upvotes: 0

Martin Zeitler
Martin Zeitler

Reputation: 76579

you may need to download a current version of the google-services.json and authenticate with this one instead, because there most likely is/are whole other account(s) being defined by it; despite the new FCM endpoint still may process the authentication with the previous GCM credentials.

Upvotes: 1

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