signInWithPopup - Chrome Extension Not Working

I've followed the instructions [here](https://firebase.google.com/docs/auth/web/google-signin#authenticate_with_firebase_in_a_chrome_extension). I'm using `auth.signInWithPopup()` to connect with a provider. It's properly set up and running in `background.js`. I'm getting this error when triggering the login:

```"This domain (site) is not authorized to run this operation. Add it to the OAuth redirect domains list in the Firebase console -> Auth section -> Sign in method tab."```

I add it. The error is gone, the popup displays, but it's blank. It gives no error. Any ideas? Anyone else able to authenticate via chrome extension using a provider?