Network error from Firebase auth on deployed app


I have a react native mobile app using expo which I have just published to expo host in order to share with a user. The app uses Firebase auth.

Users cannot sign up, they can only sign in. The sign up is done via the app and the app creates the user in Firebase with an email, password and the emailVerified set to true. Signin is set to email/password and is not via an oath provider.

However, the user cannot then sign in on the deployed app, getting Network Error on each attempt.

Everything works fine on local host on a dev version of Firebase auth.

I also have the same setup (in prod) for a react app which is hosted from the client’s domain. The user can log in to the react app without any problems.

The expo version I’m using is 43.0.3, react-native 0.64.3, firebase 8.10.0. Sign in is via an Android tablet.

What am I missing? Any help would be much appreciated.