Shared calendars keep disappearing from our Exchange account
The user you authenticate with on the service object must have full access permission to the calendar you want to save the appointment on. This can be done via Exchange Management Console or PowerShell
Here is a post on Microsoft forums:
Their proposed solution:
If you go into Active Directory Users and Computers, view the properties on one of the problematic accounts, click on the Security tab, click the Advanced button, the "Allow inheritable permissions..." checkbox needs to be checked. In our case, it was not checked, so we need to check it. After doing that, we then needed to remove and add back the full access delegate permissions using the Exchange Management Console.
Another user posted: We just found the resolution for this one as well. Although the mailbox had the proper credentials, apparently the calendar didn't. Once we added that admin account to the calendar, the error went away and the calendar entries are posting as they should.
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