Yesterday, I mistakenly deleted what I thought was a defunct Firebase project, but it turned out to also delete a live Google Cloud project. Upon realising my mistake today (when Google SSO stopped working), I restored the project. I have also restored the oAuth 2.0 credentials.

However, I still receive “Access blocked: authorisation error. The OAuth client was deleted.”

The oAuth consent screen in the cloud console says: “Pending developer action” but no actions/issues are listed. It’s not clear if I’m awaiting verification or something else is needed.

If I try to add new oAuth 2.0 credentials, I get the error: “The brand that you’re trying to edit has been deleted. Recreate your brand.” but that link just takes me to the oAuth consent screen settings again.

Any ideas?

This post has an almost identical problem, but no clear solution.