When attempting to share Calendars between users via powershell, I encountered an error stating:
The Sharing policy doesn’t allow you to grant certain permissions to users on CalendarFolder folder “Calendar”
The first cmdlet I used was:
Add-MailboxFolderPermission -Identity nick.lastname@domain.com:\Calendar -User claire.lastname@domain.com -AccessRights Author
This returned the error above.
I tried sharing again, referring to the users with just their aliases:
Add-MailboxFolderPermission -Identity nick.lastname -User claire.lastname -AccessRights Author
This resulted in the following error which points to the real issue:
The specified mailbox “nick.lastname” isn’t unique.
In this tenant, we have multiple users with the same alias and different domain names - eg. nick.lastname@domain1.com and nick.lastname@domain2.com
The Add-MailboxFolderPermission cmdlet might require that the users have unique aliases. To resolve this, I changed the user’s alias to something unique using the Set-Mailbox cmdlet
Set-Mailbox -identity nick.lastname@domain1.com -Alias nick.lastnamedomain1
Once this was resolved for the affected users, I could add the mailbox permission without issue by referring to the users by their unique aliases:
Add-MailboxFolderPermission -Identity nick.lastnamedomain1:\Calendar -User claire.lastnamedomain1 -AccessRights Author
