Mail certificate for Roadrunner expired. - Time Warner Internet

This question is about "Mail certificate for Roadrunner expired.", with Time Warner Cable internet and apps. Trying to access Mail on iMac, message says, “The certificate for this server is invalid.” The server is a (Roadrunner) server. So it doesn’t appear to be an “Apple problem,” but rather on Roadrunner’s end.

It refers to a “” certificate that expires October 29, 2020.

“Mail can’t verify the identity of the server “”

Spectrum claims it’s an “Apple problem.” ????

Mail certificate for Roadrunner expired.?