Hi We are running mixed Exchange 2007 / 2010 environment. All clients are Outlook 2007 SP2. This is the set up: UserA is on Exchange 2010 "Marketing Comms" shared mailbox is on Exchange 2007 There is a DL named "Marketing DL" UserA has 'Send As' rights on "Marketing Comms" So UserA is trying to send a marketing email to the Marketing Comms DL. Looks like he has the correct rights etc. But when he tries to send the message he gets this message: "You can't send a message on behalf of this user unless you have permission to do so." Is there any logging etc I can increase to find out why this is?

Can the user send to anything else as that account? Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Hi, From your description, you need to check the following: <1>Check whether OWA has this issue <2>Check the result after recreating UserA’s profile <3>If the above doesn’t work, please check whether you have configured send-as permission Hope it helps. If the issue still occurs, please let us know. ThanksSophia Xu TechNet Community Support

Dear Sophia, What if OWA is also saying the same even after these permissions were assigned days back and AD Object security tab also shows the Send As permission? Thanks.Junaid Ahmed