For port 993, is SSL checked & authentication = Password?
Could this be it?
Gmail send but not receive...
Here are two steps that have come in handy in related situations
1) login to gmail on your computer or device via a web browser
2) once logged in successfully, go to this URL to unlock:
I give much thanks to my 14 year old son for helping me to resolve this issue.
For anybody else who encounters this problem, perhaps this will work for you too.
What helped was renewing the DHCP lease. To do this, go to System Preferences, Network, Advanced, TCP/IP, and click the renew DHCP lease button.
Worked like a charm, and I'm back in action!
Thank you to BDAqua for attempting to help me.