Firebase Phone Authentication Internal Error 503 with Error code 33

Question

I am aware of this post What does the Firebase Authentication error code 33 FIRAuthInternalErrorDomain mean?

But at time of writing there are no issues reported on firebase status dashboard.

https://status.firebase.google.com/summary

So we're incredibly stumped. This has started happening without any recent changes, and is only happening on iOS platform.

Also, it does not happen on certain devices within our developer team - every other device we have tested with thus far has this error.

Any insight or hints highly appreciated, thank you.

Answer 1

We have discovered the issue in our case - our APNs certificates had expired and we did not figure this out until lots of clicking around and testing.

It was still working on Android and Dev devices because our Development certificate was still active!!!

Hope this helps someone else in the future. Use Auth Keys:D