Customer has an Outlook 2007 client logging onto an SBS 2011 server. When we log on to the user's Outlook 2007, and try and send an e-mail, we get back 'You can't send a message on behalf of this user unless you have permission to do so. Please make sure you're sending on behalf of the correct sender, or request the necessary permission'.
The thing is, we're pretty sure it's not an Exchange server permissioning issue, because when we log onto the webmail interface as that user, we can send and receive e-mails. We've rebuilt a new user profile in Outlook for that user, but we still get the same error message.
Anybody seen this before?