Same with me. Tried everything, and I mean everything. Eudora is a POP3 program, only. I have deleted and reinstalled the Eudora program. I have researched and repeatedly changed ports and tried different ports. Nothing has worked. Connection just times out.
Comcast must have just changed something. PLEASE HELP COMCAST!
Eudora hasn't been developed or supported for several years now. Back in 2013 or thereabouts, users were advised to migrate to Mozilla Thunderbird. Research I've done indicates that Eudora does indeed allow for the use of IMAP, but I've never tried it myself.