FCM getting MismatchSenderId

Question

I have an application that uses Google FCM for sending push notifications.

When i send a push notification to a group of users, i get a response of MismatchSenderId for some of them. Even though, all users have the exact same application. How can some of the users get a success response and others get a MismatchSenderId?

I have researched a lot and made sure I have added all prerequisites that FCM needs.

Any suggestions?

EDIT:

Sample response:

{"multicast_id":5340432438815499122,"success":0,"failure":1,"canonical_ids":0,"results":[{"error":"MismatchSenderId"}]} 

EDIT 2:

Here is the server side sending code (PHP):

$fields = array (   'to' => $token,   'data' => $data );  $headers = array (   'Authorization: key=AIza**************************',   'Content-Type: application/json' );  $ch = curl_init(); curl_setopt( $ch,CURLOPT_URL, 'https://fcm.googleapis.com/fcm/send' ); curl_setopt( $ch,CURLOPT_POST, true ); curl_setopt( $ch,CURLOPT_HTTPHEADER, $headers ); curl_setopt( $ch,CURLOPT_RETURNTRANSFER, true ); curl_setopt( $ch,CURLOPT_SSL_VERIFYPEER, true ); curl_setopt( $ch,CURLOPT_POSTFIELDS, json_encode($fields) ); curl_exec( $ch ); curl_close( $ch ); 

UPDATE:

It seems that the issue has been resolved with the SDK updates. I am using now the latest com.google.firebase:firebase-messaging:9.6.1, I don't get "MismatchSenderId" anymore.

Answer 1

Firebase has upgraded their server keys to new version. Use new keys instead of old one.

go to settings->project settings->cloud messaging tab

Answer 2

I found this solution:

• First I check server key is correct or not it was correct which is like AIzaXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
• Then I check Sender Id like 79XXXXXXXX it was also correct.
• Main issue was in device_ID(UDID) to whom I have to send the notification. Actually DeviceId we got on android side in FCM is different than GCM. You can't use GCM created DeviceId in FCM.