# 52104: Mismatched GCM/FCM sender ID

Log Level: ERROR

## Description

### Possible causes

* GCM/FCM API Key provided is not allowed to send notifications to the registration token.

### Possible solutions

Make sure that you are using an API Key/Secret that is allowed to send notifications to your application.

* Add the Project number of the Google Developers Console/Firebase Console project that the API Key/Secret belongs to to the allowed sender IDs of your application
* Alternatively use an API Key/Secret from a project that is already allowed to send notifications to your application