Requested entity was not found when trying to send a push notification using Firebase Cloud Messaging in Firebase Cloud Functions

Question

I'm trying to send a multicast notification via FCM from a Firebase Cloud function with the following code:

const message = {
    tokens: recipients,
    notification: {
        title: title,
        body: body
    },
    data: {
        projectPartnerId: projectPartnerId
    }
};
return admin.messaging().sendMulticast(message);

And none of the push notifications is getting sent. Each response contains an error with the same message: "Requested entity was not found".

I enabled the API in the Google Cloud console (which was not mentioned anywhere in the Firebase documentation but apparently that was necessary). I don't know what else I can do. And all the other questions I could find related to the HTTP API or the legacy API. I'm using the latest version of the Firebase Admin SDK.

Answer 1

Figured it out. So apparently, this error happens when the FCM token I'm trying to send to is not registered anymore, as evidenced by the "messaging/registration-token-not-registered" error code. In that case I just need to remove this token from the user's token and be done with it.

Answer 2

I recently ran into this issue when setting up push notifications for an iOS app. I found a successful fix by following a fix posted on a GitHub thread via this answer. The issue was that in the Info.plist FirebaseAppDelegateProxyEnabled was set to bool rather than a string so:

    <key>FirebaseAppDelegateProxyEnabled</key>
    </false>

becomes

    <key>FirebaseAppDelegateProxyEnabled</key>
    <string>0</string>

The GitHub comment also describes implementing flavours via a medium post and adding Firebase/Messaging to the Podfile, this is related to using Flutter to build an iOS app. My project is built with Flutter but we didn't need to implementing anything around flavours or update the Podfile as it's managed by Flutter itself.

Answer 3

As stated by @user1123432 I just did like below:

try {

// Logic to send a push notification goes here

 catch (e: Exception) {
    logger.error("Firebase Notification Failed: ${e.message}")
     if (e is FirebaseMessagingException) {
        logger.info("Firebase Notification token for the user: ${user.userName}, errorCodeName: ${e.errorCode.name}, messagingErrorCodeName: ${e.messagingErrorCode.name}")
        if (e.errorCode.name == "INVALID_ARGUMENT" || e.errorCode.name == "NOT_FOUND" || e.messagingErrorCode.name == "UNREGISTERED") {
            myNotificationTokenRepo.clearTokenByUserId(user.uuid)
            logger.info("Deleted Firebase Notification token for the user: ${user.userName}")
        }
    }
}