I'm on a Mac. Why can't share my calendar with my colleagues?

There is a known issue with Outlook for the Mac where granting someone Free/Busy or Limited Details access to your calendar will not allow the person you are sharing with to see any information on your calendar at all, including Free/Busy. Outlook for Mac users may grant reviewer permissions or higher to colleagues who need access to their calendar information.
 
For more information please see the following articles regarding this issue:
 
https://community.office365.com/en-us/f/158/t/409064
https://support.microsoft.com/en-us/kb/2876443