All of our mailboxes have been migrated to Exchange 2007. The majority of users are still using Outlook 2003 for the client. The problem is, if someone shares his/her calendar, and sets Anonymous and Default to reviewer and even explicitly sets another user to reviewer, the user can see the calendar in Outlook 2003, but not in OWA 2007. It produces the following error:
"You do not have permission to open this mailbox. For access or for more information, contact technical support for your organization. "
When I look at the security logs on the server on which the mailbox lives, it shows successful logon attempts by the user at the time of the attempts to connect to the calendar.
I have confirmed that /everyone and NT Authority/Anonymous have reviewer access to the calendar folder and the root of the mailbox using PFDAVAdmin. Any help would be appreciated. Thanks.