Recently we migrated from Win2k3 to a Linux Zentyal server running samba 4 as a PDC. We have 15 workstations that were on the Win2k3 domain previous (ess.local) and we switched these over to workgroup and back onto the Zentyal server (also ess.local) that operation went flawless and the workstations appeared fine. However that was only skin deep. Upon launching Outlook and filling in the POP3 credentials it failed with a -ERR PASS [AUTH] type error. After much diagnosing I have used wireshark to determine that regardless of the password entered for the POP3 account Outlook 2013 is sending a /r/n. Other small mail clients work fine as does a raw telnet session on port 110.
I tried many different outlook command line switches, deleting registry entries for Outlook to no avail. Something I discovered afterwards was I could not go into Control Panel -> Credential Manager. It errors with 0x80090345 which isn't a terribly useful error. Any webpages that have username/passwords will not save (in fact it doesn't even let me click Not for this site).
A fresh install of Win8.1 in a VM does not have this issue when joined to the domain. Does anyone have any ideas what I could pursue to help solve this?