Uh oh, just retried after submitting my last message… and it worked.
I’m getting this same error too, it’s when trying to setup the plugin. It connects my Google account but right after going to the callback URL I see that error.
And I can’t access the Site Health tab because it gives a timeout. Console shows a 404 on an URL:
https://sitekit.withgoogle.com/v2/site-management/setup/ 400
