On some user accounts when they tried to open a shared calendar they get to the language selection screen then after selecting the language, time zoneand clicking on ok they get this messageYou do not have permission to open this mailbox. For access or for more information, contact technical support for your organization.we have tried to access it via outlook and it works fine, permissions are set correctly to publishing authors. this is currently only affecting some users, other users on the same exchange server have no problem. any help will be appreciated.

To open mailbox or calendar in OWA you need to have Full Access permission on mailbox.It works in Outlook with calendar or folder level permission like Publishing authors or reviewer but to open in OWA it requires Full Access.How to Enable Explicit Logons in Outlook Web Accesshttp://technet.microsoft.com/en-us/library/aa998830.aspxAmit Tank | MVP - Exchange | MCITP:EMA MCSA:M | http://ExchangeShare.WordPress.com

I have the same set of permissions on all my users and this is only happening to 2 users. is it not full access, is explicit access to the calendar.

Hi,Shared Calendar Mailbox Name: "XYZ"User accessing the shared calendar : "ABC"1. Login into the mailbox of "XYZ" using Outlook Web Access 2007 at least once2. Use the below link to access shared calendar of user "XYZ"https://mail.contoso.com/owa/XYZ@contoso.com/?cmd=contents&f=calendarMore information to share with you:Understanding the difference between explicit logon and accessing another users calendar using Web Parts in Exchange 2007http://msexchangeteam.com/archive/2006/11/28/431665.aspxRegards,Xiu