OK Bob, I 've got some answers. If I run Eudora and select Tools - Options- Checking Mail, I see that the current option is Secure Sockets Required when Receiving. After attempting to get the mail from the server, I can use the “Last SSL Info” button to get info about the failure.
It says "Server’s SSL certificate was rejected. Server’s IP 98.139.211.220, SSL Version TLSv1.
There is another button to click: “Certificate Information Manager” Which shows a list of “Trusted Certificates”. Top of the list is one generated by Avast.
I can “export” it, which in this case saves a copy on my hard drive called certificate.cer.

What is missing, I think is a way to get this certificate to my email server.

Since you guys at Avast generated this certificate, isn’t there someone who can tell me what to do next?