MismatchsenderId can happen while sending the push notifications primarily due to a conflict between the private key uploaded on MoEngage dashboard and google-services.json file in the Android project. Kindly ensure you use the private key and the json file from the same project.

Incorrect google-services.json file

Every Firebase project will have a Project ID. There are couple of things to check for correct json file.

• This Project ID should be same in the google-services.json file that is present in your Android app.

• Package name in your manifest file also should match the package name in the google-services.json file 

Incorrect private key on MoEngage Dashboard

To verify if you have uploaded the right private key, the project_id in the private key should match with the Firebase Project ID. 

You can open the private key json file in any text editor and it will have the project_id key with value as your project ID.

Private key is usually generated from service accounts page, don't generate a new key if you already have a key.