Firebase Messaging Error in Functions

Question

in my project I use Firebase Functions to send message via FCM. I use this API:

admin.messaging().send()

Recently and not for all token that I use to invoke it, I got this error:

Error: Requested entity was not found.
at FirebaseMessagingError.Error (native)
at FirebaseMessagingError.FirebaseError [as constructor] (/user_code/node_modules/firebase-admin/lib/utils/error.js:39:28)
at FirebaseMessagingError.PrefixedFirebaseError [as constructor] (/user_code/node_modules/firebase-admin/lib/utils/error.js:85:28)
at new FirebaseMessagingError (/user_code/node_modules/firebase-admin/lib/utils/error.js:241:16)
at Function.FirebaseMessagingError.fromServerError (/user_code/node_modules/firebase-admin/lib/utils/error.js:271:16)
at /user_code/node_modules/firebase-admin/lib/messaging/messaging-api-request.js:140:50
at process._tickDomainCallback (internal/process/next_tick.js:135:7)

How can I solve it ? I'm sure some time ago it works and these errors are not.
Any changes in Firebase?

Answer 1

This error means the token you are trying to send the notification, doesn't exists.

You must add your send code on a try catch block, and, depending on the error, erase (or invalidate) the token on your base.

  try {
    ...
    sendYourNotification(token);
    ...

  } catch (error) {
    if (
      [
        'The registration token is not a valid FCM registration token',
        'Requested entity was not found.',
        'NotRegistered.'
      ].includes(error.message)
    ) {
      // invalidate current token
      // find the user and remove this token
    } else {
      // Log it, because is some really unexpected
    }
  }