Once again, I’ve went many months between posts. Sorry. Life has just been crazy! Since the last post we’ve moved to a hybrid config with Exchange 2010 and Office 365.
An issue I ran into a while back was with an on-prem user not able to see free/busy calendar info for anyone else, on-prem or 365. At first I thought it was a problem with the hybrid configuration because it was initially reported that the on-prem user couldn’t see free/busy info for people already moved to O365 (and I had just setup the Hybrid configuration). However after digging into the details, it turns out they couldn’t see free/busy info for anyone in the Org regardless of the location of their mailbox. AND, they could access that info from OWA! It was only broken in Outlook. And the final head scratcher, the user hadn’t changed their password recently and wasn’t routinely getting locked out of AD.
It took some time to track down, but eventually it was found to be an old saved credential in the Window Credential Manager. Deleted that, relaunched Outlook, and *poof*! Free/busy info works! I have no idea why it simply broke that part of Outlook and didn’t generate any failed login attempts in Exchange, nor did it lock out the AD account. It simply broke Free/Busy info (and only free/busy).