This one is driving me absolutely crazy, hours and hours spent on this with no luck. This is 2007/2013 env. The issue is, if I move a mailbox to 2007 then 2013 OWA is fine, then if I move the mailbox back to 2007 I can't access the mailbox via OWA when going through a 2013 CAS server. yes I've read the posts about permissions inheritance etc.. yes I've cranked up AD and OWA logging nothing.. yes I've imported the IIS logs into log parser and I'm seeing various errors mostly 302. Yes, I've ruled out 2007 servers, it's 2013. If I recreate the mailbox it works then when move back and forth from 2007 to 2013 problem re-appears. Yes, I have dumped AD attributes and compared them with working and non working mailbox can't find anything. Yes, I've rebooted servers. Yes this happens with multiple mailboxes.
In fact I have this example right now makes no sense. I have two 2013 servers, if I go through the 2013 servers CAS servers to access the mailbox using OWA that resides on the 2007 server, it works through one server and the other it doesn't with the above errors. I'd love to hear suggestions.. I'm at the end of my rope