I am trying to migrate my android app. I followed the documentation and migrated everything else but stuck with token generation. I followed the following post /a/78575180/27368045 , and I am getting the following log
getAccessToken: Error getting access token for service account: 400 Bad Request POST https://oauth2.googleapis.com/token {"error":"invalid_grant","error_description":"Invalid grant: account not found"} . I tested my json file using google cloud cli and I am successfully getting access token but don’t understand why I am getting the above when using in my app. Can anybody make me undertand this issue , how with the same json I am able to get a token with cli but not in my app ? And how can I fix it ?

private void sendNotification(String message, String userId, String otherUserId) {
DatabaseReference tokensRef = FirebaseDatabase.getInstance().getReference(“FCMTokens”);

I’m in the process of converting some code that sends Google Cloud Notifications to an Android app so that it uses the more modern Firebase notifications.

How to send Upstream FCM messages from iOS? (from 2017) shows that Firebase used to have an option to send messages from iOS using Messaging.messaging().sendMessage().

How to send Upstream FCM messages from iOS? (from 2017) shows that Firebase used to have an option to send messages from iOS using Messaging.messaging().sendMessage().

I’ve read Google’s documentation on integrating Firebase Cloud Messaging. Specifically, I’m writing the server part in Golang, using the firebase.google.com/go/v4 library. I’ve set everything up, but whenever I send a request, I always receive the message:

The FCM documentation states that From the server, you can subscribe or unsubscribe up to 1000 devices in a single request. If you provide an array containing more than 1000 registration tokens (devices), the request will fail with the error messaging/invalid-argument.

when i send push notification, facing issue messages are undelivered and connection was closed.
we need to fix the connection was closed issue fix.some time i am getting not yet implemented Error.
why it is failing with connection was closed error?.
we are tried with notification payload and need to save

We are using Java Rest Client to hit the FCM HTTP V1
i am getting check the payload issue, while passing Delay_While_Idle in AndroidGCMOptions

I’m currently rebuilding a PHP 5.6 application into Java, which is expected to go beyond June. Until then, I need to ensure that push notifications continue to be sent by migrating them.