If you are authenticating a domain for email using DKIM you may get stuck at "Authenticating Email" and email authentication is not confirmed:
This is actually working. When you click on ' Start Authentication' button and if your DKIM record at your DNS host is not propagated you would see a red error message stating that we could not locate the DKIM record and that it could take up 48h for the record to propagate.
The Google tech added:
"Actually before there was green "Authenticating email" status with a check-mark. But that was change to just 'Authenticating email' (I have no idea why)"
So it's working!