I updated Saturday 23/8-2014 from the Kubuntu PPA on 14.04, and initially thought it was just a quiet weekend ;) After checking with my webmail (RoundCube) I could see that I had received several mails, that KMail didn't pick up. I use a hosted mail service running Courier IMAP, and I have confirmed the same issue with another user also using Courier IMAP. I'm not very keen on trying to delete/create a new resource, as I have dozens of filters and dozens of folders each with different setups, so it would take me hours to recreate the setup. How can I debug the cause of this so I can provide proper info?
I've marked this as git master because 4.14 wasn't available in the list.
I have the same problem as reported by Thomas, but I'm running Debian Sid, with kontact 4.14
The mail accounts which stopped working for me seem to use Courier as well. Just send a mail to my gmail account (from yahoo) and that does work.
The report from the server when telnetting to it is: "* OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION STARTTLS] Courier-IMAP ready. Copyright 1998-2011 Double Precision, Inc. See COPYING for distribution information. Connection closed by foreign host"
*** This bug has been marked as a duplicate of bug 338186 ***