User can access other user calendar & tasks with NO shared access given

[Thetraininglady]

I have two users set up with M365.

In Outlook User1 can go to Calendar or Tasks and see the Calendar and Tasks for User2.

User2 has has removed Shared Access to the Calendar. User2 has never given shared access to Tasks. Yet User1 has access to both. I've gone into the Share Permissions for User2 and double checked and User1 def not there with access - in fact no other users have access. Yet User1 can go and create a new Task for User2. User1 can go into User2 Calendar and create an appointment.

How???

[#2]

Hi @Thetraininglady 

I understand User 1 has access to User 2's calendar and tasks.

Do they both belong to any groups that gives them access to their calendars?

Troubleshoot the issues with some of these steps:

Remove Cached Credentials: Ask User1 to sign out of Outlook and sign in again.
Check Admin Settings: Check the settings with permissions, free busy information for the users. 

Test in OWA: Ask User1 to log in to Outlook Web App (OWA) and check if they still have access to User2’s Calendar and Tasks.  This way we can check if the issue is with Outlook desktop. 

If you find this information helpful, please mark it as best response which will assist others with the same question.

/Temitope Victoria
#temitopevictoriacompany