Outlook Calendar "Free/Busy issues" (new org accounts)

Iron Contributor

Hi! We have noticed something strange for a few of our new org accounts.


The calendar sharing setting "availability only" that we have orgwide doesn't apply in Outlook (classic app). Error when viewing said calendars and the scheduling assistant is greyed out. In Outlook web you can view said calendars and free/busy works as intended. But if you use the scheduling assistant the calendar is again greyed out. 


In Teams and in Outlook mobile the schedule assistant works as intended. And all the other thousands of users have no problems.


We have tried changing the sharing settings to view details or add unique calendar permissions to just a few people on said calendars but still no luck. Tried reinstalling Office suit and new profiles in Outlook etc.


Anyone with similar issues or anyone with ideas to solve this? Have reported this to MS but no luck with the support.  See attachment

3 Replies
First thing to check here are any issues with autodiscover - use the RCA tool externally (https://testconnectivity.microsoft.com/) or the SaRA tool on the local machine (https://www.microsoft.com/en-us/download/details.aspx?id=100607). Next, make sure EWS works as expected (same tools) and double-check the EWS-related properties on the mailbox:

Get-CASMailbox email address removed for privacy reasons | fl EWs*

If you are in Hybrid, there's a whole other set of checks to perform.
Thanks Vasil! For some reason after weeks of troubleshooting this magically works now. We didn't change anything.
You're welcome :D