Shared calendar - Removed user still has access

[Kepana]

Hi

In our organisation, the default setting for calendars is that all users can see if other colleagues is availble or busy. This is of course quite common.

But in some cases, for special projects some users shares their full calendar with specified users.

In those cases, User A adds user B to the shared list in the Outlook client. User B then gets a e-mail saying that User A wants to share the calendar and User B can click "Accept" and then get access to the calendar.

When the project is over User A removes the access for User B and User B will then lose the access. However. If User B goes back to the initial e-mail that was received about the calendar being shared, User B can click on "Accept" again and get access to User A's calendar again.

We have been able to re-create this with several accounts. Is there anybody that has any idea how we can make sure that the access is revoked for User B permanently?

[#2]

Hi Kepana,

Did you also check User A's MailboxFolderPermission via Powershell?
Connect-ExchangeOnline
Get-MailboxFolderPermission -Identity user@domain | FL

Can you also try to enforce the removal of the MailboxFolderPermission of User A via PowerShell?
https://learn.microsoft.com/en-us/powershell/module/exchange/remove-mailboxpermission?view=exchange-...

You can also try to first set and then immediately remove MailboxFolderPermission of User A via PowerShell.

In the past, some customers had Exchange Online mailbox issues that could only be resolved by, for example, setting ("overwriting") parameters explicit to $null.

[#3]

Thanks for the tip, I will take this with my team!

//Kepana