Recently i got the fact, that mail hosting changed available connection modes. Initially i used TLS. Since some time (not so far ago) kmail became unable to send emails via that provider - don't recall exact error message, but it was about lack of server reply, as if it did not exist. Problem disappeared when i made auto-detection in outgoing messages settings, now it was simply SSL. There could be option, how to handle such case: nothing (current), auto-detect, ask user (more exactly - show proper settings dialog). Reproducible: Always
This bug has only been reported for versions before 4.14, which have been unsupported for at least two years now. Can anyone tell if this bug still present? If noone confirms this bug for a Framework-based version of kmail2 (version 5.0 or later, as part of KDE Applications 15.12 or later), it gets closed in about three months.
Just as announced in my last comment, I close this bug. If you encounter it again in a recent version (at least 5.0 aka 15.08), please open a new one unless it already exists. Thank you for all your input.