I have a user that’s having most calendars shared with them show ‘no connection’ and when in schedule view it shows the calendars aren’t shared with them even ones I've explicitly shared while troubleshooting this problem.
Some calendars work some of the time, but most don’t work at all. There doesn’t seem to be any connection between the ones that do work and they’ll go back to showing no connection every few times I reopen Outlook.
I’ve checked that they definitely have the right permissions on the calendars
I’ve signed out and back into his O365 account
I’ve repaired the ost file with scanpst
I’ve done an online repair of O365
I’ve run updates on both the laptop and Outlook
I’ve run sfc /scannow with no issues
I’ve checked the internet connection and work offline settings
I’ve checked Outlook in safe mode and disabled add-ins with no difference
I’ve changed the cached exchange mode ‘download shared folders’ setting and disabled cached mode entirely with no difference
The user could definitely view these shared calendars in the recent past and it doesn't seem to be effecting anyone else.