Error message: "Verify the Certificate."

I've had the PB for over a year and for the first time the above error message cropped up yesterday. The error message reads as follows:

"You are connecting to: smtp.sonic.net
The server certificate is not configured for the domain.

* .mail.sonic.net
Issued by: EssentialSSL CA
Expires: Wed oct 31 2018 11:59:59 PM
Etc. etc.

When i click on the box that says "Accept" the problem goes away and I am able to resume reading email or the internet. But every once in a while the error message pops up again. Finally, in desperation I clicked on the box in the lower left that reads: Always trust "* .mail.sonic.net"

What is happening and am I doing the right thing? I might suspect that maybe the problem is at my ISP provider end. The kind of service i have is a combined telephone and internet service where my phone connection with AT&T was dropped six months ago. Sonic.net claims it is not a VOIP type of service, they just ported my AT&T connection over to their Server with no change in home wiring.

Please do not post duplicate threads on the same topic.
Your other thread has been closed and this one will remain open.

Good luck with your issue!