Could not create an account as [email protected] to your Firebase project issue

I have been getting this error when trying to manage my data in Flutterflow:

I found a few topics raised on it in the community but the solutions aren't working for me. One suggested to create another project, but that didn't work.

I found this:

On this page:

https://docs.flutterflow.io/data-and-backend/firebase/firestore-database-cloud-firestore/firebase-content-manager

But URL is broken.

Has anybody encountered this recently and has a fix for it?

Cheers