Sign in with Google: Access blocked: This app’s request is invalid

jhaaaa · January 6, 2026, 5:38pm

A user tried to sign in with Google yesterday and let me know they are getting this error. I logged out and tried to get back in via sign in with Google and am getting the same error:

When I click error details, this is what I get:

Error 400: redirect_uri_mismatch
You can’t sign in to this app because it doesn’t comply with Google’s OAuth 2.0 policy.
If you’re the app developer, register the redirect URI in the Google Cloud Console.

Request details: redirect_uri=XMTP Improvement Forum flowName=GeneralOAuthFlow

Can you help us get sign in with google working again, please?

Thank you!

J-Ha

jhaaaa · January 8, 2026, 8:14pm

A friendly ping on this one, @pfaffman - any thoughts on this? Thank you, as always!

pfaffman · January 8, 2026, 8:17pm

You changed the URL of your site, so you need to update the Google App with the new URL.

You need to add the callback and url to the google config

jhaaaa · January 20, 2026, 5:13pm

@pfaffman Just wanted to share the fix that finally resolved this, if helpful for the future - our Google OAuth client secret and ID went inactive for some reason. As soon as I updated them with new ones in Discourse - Sign In with Google started working again.

Hope all is well!

J-Ha

pfaffman · January 20, 2026, 5:15pm

If it’s working, it’s working, but the error you showed was because the hostname changed. Perhaps someone added the new host name and callback as well.

Also, it doesn’t work for me, but maybe it’s not supposed to?

jhaaaa · January 20, 2026, 5:41pm

We added a new host name and callback – and it didn’t work. Then we added this and it worked - so maybe the combo as you suggest!

But oh no! It should work for anyone who wants to use Sign in with Google! Back to the drawing board!

pfaffman · January 20, 2026, 5:54pm

Aha! So that was necessary, but not sufficient.

I think this: