Grab a session log and see what is going on.
Should be pretty easy to spot the culprit (my money is on Exchange :) )
Hi dilberts_left_nut and all,
Well, too bad, I am not in the business of finding culprits, just not enough time, maybe when I retire (if ever) :) Seriously, DavMail turned out to be rather straightforward solution to my IMAP/Exchange headaches. This is free GPL software that runs on PC, presenting itself to PMAIL as POP3 server running on localhost. When polled by PMAIL it logs onto Exchange and retrieves new mail from it using .... its web interface! Works without a hitch so far, fingers crossed. Configuration is extraordinarily simple: run DavMail and supply Exchange web interface address to it. Enter "localhost" for PMAIL POP3 server with username and password required for Exchange login and make sure POP3 port is the same as in DavMail - that's it! Now PMAIL is happy fetching mail through tried and true POP3.
DavMail (http://davmail.sourceforge.net ) is being actively developed by Mickaël Guessant (just downloaded a new version) and sponsored by no else but French military. It is specifically aimed at Exchange to make it accessible by standard (i.e., not M$) protocols. There are few similar gateway products on the net, but most of them are out of date, hard to configure and unlikely to work reliably with Exchange anyway. DavMail offers POP3 which I am currently using, IMAP which I may try again after some cool off period :), SMTP for sending, LDAP to access Exchange address books and Exchange calendar support. It can be run as a server on local network to be accessed by multiple clients. It is just a shame that someone's talent has to be used specifically to correct incompatibilities created by Micro$oft.