We have a shared mailbox that other users send work requests to. Our normal procedure for giving someone access is to go into Exchange 2007 Management Console, right-click the shared mailbox, and grant Full Access to the user that needs it.
We have an employee that needs access to it. We have given her full access to it. She can open up the mailbox but she cannot send from the account. It gives her a "you do not have permission to send on behalf of the specified user." Even if I grant her Send As permissions, it still doesn't work.
I have tried having her log into another computer with the same result.
We have several other employees that have the same permissions that work fine (without giving separate Send As permissions).