Q: Calendar service: IMAP errors retrieving mail

Been having an issue with our OS X 10.10.5/Server.app 4.1.5 server and Calendar invitations.

Our config is somewhat complicated by the fact that we don't use OS X mail server for our primary domain (and our primary mail server doesn't support + addressing), so we have mail enabled on our Calendar server using a secondary domain. I've gone through our OD and added the secondary domain emails to all of the users.

Can send email to external event invitees just fine.

They can respond and the messages make it to the server (I configured Mail.app on the server with the same account credentials and can see the outgoing and incoming messages/send and receive manual messages).

The problem/issue is that the python script that runs the Calendar service seems to error out trying to access the IMAP inbox. Before I spun up Mail on this same server, I had tried to make it work with a Kerio mailserver (set up wildcarding so the + addresses would go to the Calendar server address). Same issue. Am starting to wonder if it's a server configuration issue.

The issue with the Calendar service not able to read messages from the IMAP inbox is that the event never gets updated with whether the invitees accepted or declined the meeting.

I've tried with SSL on and off, I've made sure the passwords are correct. I've manually edited/inspected the plists (nice cleartext email password in the plist, which is the right password) and serveradmin calendar stop/start. No change in behavior. At this point, I'm not sure why the Calendar service fails to authenticate. About to replicate my config onto a fresh VM and see if a newly-configured Server repeats these errrors (since it happens with 2 different email servers)... Only other thought is that perhaps it doesn't like the second domain, even though all of the OD users have user@domain1.com and user@domain2.com addresses in their records..

2015-09-18 04:54:41-0500 [-] [caldav-3]  [IMAP4DownloadProtocol,client] Unhandled Error

2015-09-18 04:54:41-0500 [-] [caldav-3] Traceback (most recent call last):

2015-09-18 04:54:41-0500 [-] [caldav-3] Failure: twisted.internet.error.ConnectionDone: Connection was closed cleanly.

2015-09-18 04:54:41-0500 [-] [caldav-3] 

2015-09-18 04:54:41-0500 [-] [caldav-3]  [IMAP4DownloadProtocol,client] [txdav.caldav.datastore.scheduling.imip.inbound.IMAP4DownloadProtocol#error] IMAP login failed for com.apple.calendarserver@domain.com

2015-09-18 04:55:11-0500 [-] [caldav-3]  [IMAP4DownloadProtocol,client] Unhandled Error

2015-09-18 04:55:11-0500 [-] [caldav-3] Traceback (most recent call last):

2015-09-18 04:55:11-0500 [-] [caldav-3]   File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/twi sted/protocols/basic.py", line 571, in dataReceived

2015-09-18 04:55:11-0500 [-] [caldav-3]     why = self.lineReceived(line)

2015-09-18 04:55:11-0500 [-] [caldav-3]   File "/Applications/Server.app/Contents/ServerRoot/Library/CalendarServer/lib/python 2.7/site-packages/txdav/caldav/datastore/scheduling/imip/inbound.py", line 712, in lineReceived

2015-09-18 04:55:11-0500 [-] [caldav-3]     imap4.IMAP4Client.lineReceived(self, line)

2015-09-18 04:55:11-0500 [-] [caldav-3]   File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/twi sted/mail/imap4.py", line 2360, in lineReceived

2015-09-18 04:55:11-0500 [-] [caldav-3]     self._regularDispatch(line)

2015-09-18 04:55:11-0500 [-] [caldav-3]   File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/twi sted/mail/imap4.py", line 2388, in _regularDispatch

2015-09-18 04:55:11-0500 [-] [caldav-3]     self.dispatchCommand(tag, rest)

2015-09-18 04:55:11-0500 [-] [caldav-3] --- <exception caught here> ---

2015-09-18 04:55:11-0500 [-] [caldav-3]   File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/twi sted/mail/imap4.py", line 2417, in dispatchCommand

2015-09-18 04:55:11-0500 [-] [caldav-3]     f(tag, rest)

2015-09-18 04:55:11-0500 [-] [caldav-3]   File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/twi sted/mail/imap4.py", line 2446, in response_UNAUTH

2015-09-18 04:55:11-0500 [-] [caldav-3]     self._defaultHandler(tag, rest)

2015-09-18 04:55:11-0500 [-] [caldav-3]   File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/twi sted/mail/imap4.py", line 2467, in _defaultHandler

2015-09-18 04:55:11-0500 [-] [caldav-3]     raise IllegalServerResponse(tag + ' ' + rest)

2015-09-18 04:55:11-0500 [-] [caldav-3] twisted.mail.imap4.IllegalServerResponse: YWVlMDhjZWVmNDkzZjUxNzY0NjgxNGEzZDI= BAD Error in IMAP command received by server.

2015-09-18 04:55:11-0500 [-] [caldav-3]