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 MismatchSen

Answer 1

I had the same problem, and I fixed it like this:

1. Go to your google fcm console
2. Select your app
3. In the left side menu find settings icon (standard wheel)
4. Click on it and after click on project settings
5. Now copy your server key and paste it in php

Voila...