Andy M

Note: The steps below are not recommended by Microsoft . Verify that modern authentication is enabled before moving forward. When an Exchange users is migrated to Office 365 they may get constant credential prompts. Even if the user enters the correct credentials the prompt will come back in a few minutes. The user might also lose the ability to access shared mailboxes and public folders.  The fix is to set all of the reg keys below to 1 , doing so will enable modern authentication. Office 2013: HKCU\SOFTWARE\Microsoft\Office\15.0\Common\Identity\EnableADAL HKCU\SOFTWARE\Microsoft\Office\15.0\Common\Identity\Version Office 2016: HKCU\SOFTWARE\Microsoft\Office\16.0\Common\Identity\EnableADAL All versions 2013+ Create this even if you are on 2016 where it is enabled by default HKEY_CURRENT_USER\Software\Microsoft\Exchange\AlwaysUseMSOAuthForAutoDiscover Restart Outlook and the prompts should go away.  https://docs.microsoft.com/en-us/exchange/troubleshoot/modern-authentication/...

Had an issue this morning where a user could not modify another user's calendar. The user had PublishingAuthor permission to the calendar, both users were on Office 365, I had waited 24 hours after reapplying the permissions. The user could see the full details of the calendar, but she could not modify it. Right clicking on the calendar would only show the greyed out items below. Right clicking on the calendar permissions would return the error below: Cannot display the folder properties. The folder may have been deleted or the server where the folder is stored may be unavailable. Cannot display folder properties. You don't have appropriate permissions to perform this action. I created a whole new profile on a different computer to test. I waited for the cache to finish building but I still had the issue. Ultimately, the solution was to add the calendar from the Online Global Address List, and not the Offline Global Address List. Clear all of the Office/Outlook r...