We have an issue with shared calendaring: All users with Windows 10 and Office Pro 2013 can add shared calendars set to see Free/Busy, but get a “No Connection” message when the calendar opens. The opened calendar will connect if it’s set to “Full”, “Editor”, or “Delegate’ but that’s a higher level then we only want them to see Free/Busy.



Users with Windows 10 & Office Pro 2016, Windows 7 & Office Pro 2013/2016 don’t have this issue, only users with Windows 10 & Office Pro 2013.
The same users who can’t view the Free/Busy cal in Windows 10& Office Pro 2013 can log into the OWA (Outlook Web Access) and connect to the calendars and view them that way with no issue.



Exchange host is Fusion & Megapath.



We’ve tried all of the standard repairs: sfc /scannow, full windows update, office repair Quick/Online, Outlook.exe /safe, reinstall Office 2013, etc - no resolution with any of those.



We've contacted out Exchange host and Microsoft numerous times and they've offered numerous solutions but none have worked.



Has anyone seen this issue before and have any suggestion? Thank you for your time.