Consider the following scenario:
- You create a user account that does not have a mailbox in a Microsoft Exchange Server 2010 environment.
- You configure the user account to have full access permissions for a shared mailbox.
- The user logs on to the shared mailbox by using the Premium interface of Microsoft Outlook Web App (OWA Premium).
- The user tries to delete an item that is in the shared mailbox.
The Mailbox you are trying to access isn't currently available. Please try again in a few minutes.
This issue occurs because OWA Premium requires the user to have a mailbox when OWA Premium tries to create the security context. If the user does not have a mailbox, a UserHasNoMailboxException exception is thrown.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.