No access to mail database

I'm trying to open a mail database, but the system brings up the following message:

You are not authorized to access that database.

How can I resolve the problem?

I hope this doesn't sound flippant, but I suspect the problem is that you don't have the proper access to open that database. There are several reasons this can happen. Have a system administrator check the ACL (access control list) of the database to make sure that your name is listed there (or a group that contains your name).