Dude, why did you do that! The error isn’t always on our end. Check out other topics here in the community. AppSheet has been having issues since yesterday at 5:30 PM UTC-3 (Brasília time). Before doing things like this—just going ahead and deleting everything—check if there are any posts about errors on the Google/AppSheet server side. For now, all we can do is wait for the Google team to fix the bug
Your current app config is showing the auth provider as Google. This means it allows ONLY Gmail accounts to access the app. If your other email address are NOT Gmail accounts, they will be denied.
If this is the problem then you only need to change the app config to “Any Provider”. See image.
I don’t think his issue is related to accounts, although, yes, if it isn’t configured to allow non-Gmail accounts, it won’t allow them. But I believe the problem is what I mentioned. Notice that in the other thread there is a reply from the Google team stating that the issue will be resolved within 24 hours.