Firebase custom hosting OAuth not working

[William Gilpin]

My firebase app works on the autogenerated url ([APP].firebaseapp.com) - I can login with Google OAuth or email/pwd as I have configured

I have connected a custom domain as follows:

 - domain is of the form appname.uk, note it's not a subdomain like www.

 - under Hosting it is set as a custom domain, and the console shows it as "connected"

 - under Authentication it set as an OAuth Redirect Domain, type Custom

It's a web app, using signInWithRedirect 

If I connect via the auto-generated (*.firebaseapp.com) URL I can sign in with Google or with Email/pwd.

If I connect via the custom domain I can sign in by Email / pwd, but if I try to sign in by Google I get the google account selection page, then return to the app, but onAuthStateChanged is not triggered and the user is not logged in.

Is there a step I have missed to enable Google OAuth with a custom domain?

[Bassam]

Hey William,

If you are using your own custom domain hosted by Firebase, change the authDomain

from:

PROJECT_ID.firebaseapp.com/__/auth/handler

to:

appname.uk/__/auth/handler

Make sure you whitelist that new domain in Firebase console and in your Google OAuth client.

Bassam