[Tutor Pro] Social Login for Google suddenly broken

I had google login set up via settings > authentication. It was working just fine.

I changed to a new server for hosting and the social login started being buggy. It was 50/50 whether it would be successful or fail. Then it completely stopped working.

I am not certain if the server change was the cause, or if it was being buggy before then, and I just didn’t notice. But it did work a few times after the server switch.

To be sure, I revalidated ownership of my website with google, and created a completely new oauth project, copying the redirect URI from tutor settings.

Alas, even with the new client id, I get the same error:
Authentication failed.
Invalid login request.

I’ve tried different browsers, I’ve tried mobile, I’ve disabled all plugins: I can not, for the life of me, figure out the issue.

The page I need help with: [log in to see the link]