sign in error

Hi
Thank you for the lesson its really helpful.
i keep getting this issue when i try to login.

Notifying auth state listeners.
D/FirebaseApp(21644): Notified 0 auth state listeners.
I/flutter (21644): Signed in: 5LL4lM0lOVScxfF5oSmTHmvxotW2
I/flutter (21644): Error: NoSuchMethodError: The method 'call' was called on null.
I/flutter (21644): Receiver: null
I/flutter (21644): Tried calling: call()

the authentication works fine as you can see it returns uid. but it doesnt re direct to the new page i created

Start by reproducing the sign-in flow and tracing the redirect to the new page after the log shows a successful UID and the NoSuchMethodError. Identify which callback or navigation step is null; done means a successful login reaches the new page without the error.

Written by the indexing model from the issue text.