Since, according to Google Play, there hasn't been an update since March 21st, 2021, version 4.4.64, this recent bug is making me wonder what is happening.
The following is the error message:
The app failed to synchronize data. Check your certificate and retry later.
Unexpected error: The API call mail.Send() required more quota than is available.
I know it is the 23rd June today, here in England and, by now, in all of the USA. A newly-created certificate is still valid from the 22nd June. I am not getting the validation email, which suggests the mail.Send() error is significant.
I have whitelisted mictales.com
on my ad-blocker but the error doesn't change. It does look as though my certificate request is getting through, and the problem is with the email response.
I was using the same email address as attached to this post. I did try a different address, which gave the same error message. Email from other sources is arriving OK.