[Discuss] Thunderbird not connecting to Comcast IMAP server

[epp at vivaldi.net (epp at vivaldi.net)]

Beginning this past Monday, Thunderbird and the SeaMonkey suite (on Fedora 30) mysteriously stopped connecting to Comcast's IMAP mail server.

In trying to diagnose the issue, I also installed Evolution, which also failed to connect.

After removing the Comcast accounts from Thunderbird, attempts were made to add them back in, however when Thunderbird attempted to check the password, that process becomes stuck, as if Thunderbird cannot resolve the IP address(es) for the Comcast server. I let it sit like that for 15 minutes without success, then clicked Cancel.

Thunderbird otherwise connects to non-Comcast IMAP servers perfectly.

I also have Geary installed and that successfully connected to the Comcast server, yet the other three email clients could not.

Could this be an issue on Comcast's end? If it were a DNS or resolver issue, then nothing would connect.

I have Thunderbird installed on a second system and it connected to Comcast successfully on that, last night.

Thanks for any replies/suggestions.