Short answer
Firebase could not authenticate to Apple’s push service for this app. In the Firebase console open Settings, General, then the Cloud Messaging tab, and under iOS app configuration upload an APNs authentication key from your Apple Developer account with its key ID. If the project still uses an old APNs certificate, check it has not expired and replace it with a key. For web push, the same error means the web push key is missing or wrong.
Rather not fix it yourself? App Fix Ticket starts with a fixed-price diagnosis, then a fixed price for the fix before any fix work.
Why Apple rejected the push, and the fix
01
No APNs key uploaded for the iOS app
“APNs certificate or web push auth key was invalid or missing.” Firebase, FCM ErrorCode (THIRD_PARTY_AUTH_ERROR)
A new Firebase project, or an iOS app added later, has no Apple credentials until you upload them. Every iOS push then fails while Android works, because Android messages never go through Apple. In the Firebase console go to Project settings, then the Cloud Messaging tab, find the iOS app and upload the key.
02
The key ID does not match the key
“Add the key ID for the key (available in the Apple Developer Member Center) and click Upload.” Firebase, Get started with FCM on Apple platforms
The upload asks for the key file and its key ID. A typo in the ID, or a key file from a different Apple Developer team than the app, gives a key Apple will not accept. Copy the key ID from the Keys list in your Apple Developer account and upload again. If the key was revoked there, create a new one.
03
An old APNs certificate expired
“A message targeted to an Apple device couldn't be sent because the required APNs SSL certificate was not uploaded or has expired.” Firebase, FCM error codes (messaging/invalid-apns-credentials)
Older projects used APNs SSL certificates instead of a key, and those expire. If pushes worked and then stopped on every iPhone at once, check the certificate date in the Cloud Messaging tab. Uploading an APNs authentication key in its place is what Firebase’s current setup guide uses.
04
Only one of development or production is set up
“Check the validity of your development and production credentials.” Firebase, FCM ErrorCode (THIRD_PARTY_AUTH_ERROR)
Firebase lets you upload a development key, a production key, or both. If debug builds from Xcode get pushes and TestFlight or App Store builds do not, or the other way round, check that the environment your build uses has valid credentials.
Checked against the vendor’s docs on : Firebase docs: FCM HTTP v1 ErrorCode; Firebase docs: FCM error codes (Admin SDK); Firebase docs: Get started with FCM on Apple platforms.
Rather hand it over?
Fixed scope, fixed price, paid upfront. The work happens in writing; no call needed.
- from $450App Fix TicketOne reproducible bug in an existing mobile or web app, diagnosed and fixed.See scope and start
- from $450AI-Built App RescueA Lovable, Bolt or Cursor app checked end to end in 3 days, then its worst problems fixed at a fixed price.No issues worth fixing, no charge. If the Launch Check finds nothing rated medium or higher, Simon refunds the full $450. You keep the report either way. This applies to the first 10 Launch Checks bought after October 30, 2026.See scope and start
“Very responsive, attentive to fixing bugs, and completed the project as needed! Thank you!”
Related: FCM registration token not registered · Flutter APNS token has not been set · iOS push aps-environment entitlement · Expo push notifications not working