Calling verifyPhoneNumber on my firebase ios app throws "internal-error" - ios

Question

I use authentication by phone number in my flutter app. While it is working fine on Android I'm getting an error message on ios:
_firebaseAuth.verifyPhoneNumber(
phoneNumber: phoneNumber,
timeout: ...
verificationCompleted: ...
verificationFailed: verificationFailed,
codeSent: codeSent
...
static final PhoneVerificationFailed verificationFailed =
(FirebaseAuthException authException) {
Log.e(authException.message);
Log.e(authException.code);
}
Code and message both only says it is an internal error without any details.
Everything worked find before I moved the app to a new Appel developer account. This means the team id has changed.
I've also changed the team id here:
I've downloaded the google.plist again and put it into the runner directory.
The google cloud platform also shows the correct team id:
The same team id is shown in xcode in "Signing & Capabilities" -> Signing Certificate.
Changing the team id also causes loosing access to the keychain:
ITMS-90076: Potential Loss of Keychain Access - The previous version
of software has an application-identifier value of
['MKYCXH32H9.com.sykori.framr2'] and the new version of software being
submitted has an application-identifier of
['75GNKYT7HC.com.sykori.framr2']. This will result in a loss of
keychain access.
But I think the only means that data from previous versions is not accessible anyomore.

Answer 1

Since you said the issue appeared after you switched developer accounts, it's safe to assume the issue is generated by a config error.
Firebase Phone Auth for iOS docs specify a couple more steps than what you described above, namely:
Upload your APNs authentication key to Firebase. If you changed developer accounts APN auth keys also changed.
To enable Firebase SDK to use reCAPTCHA you need to add the REVERSED_CLIENT_ID to your URL Schemes box on the configuration page.
These two steps I think will solve the issue, but just to be sure you could go through all the steps from the docs to make sure nothing else is missing.