I am running Exchange 2007 SP3. When sending an email on behalf another account I receive this error: You are not allowed to send this message because you are trying to send on behalf of another sender without permission to do so. Please verify that you are sending on behalf of the correct sender, or ask your system administrator to help you get the required permission. Even though I have set up the permissions correctly trying all 3 methods.(I have checked and rechecked the process for granting access).The EMC (mail flow settings, delivery options), The EMS(Set-Mailbox UserMailbox -GrantSendOnBehalfTo UserWhoSends) and using delegates. The strange thing is that other users that I have set this up for in the past are working fine. It's seems to be just any recent attempts to set this up for a user have this problem. Nothing has changed on the mail system (that I know of) since the time it worked and now. Any help is greatly appreciated!!!

How long did you wait to take affect? Also try taking the user out of cached mode, cached mode sometimes have history of making the change not take affect.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

This has been going on for weeks. I have since restarted my DC's and all Exchange servers. I have taken the user out of cached mode, send failed. Put back in cached mode, still failed.

It seems my Exchange permissions are not being synced properly. My email account currently has a working 'Send As' permission to another account.(set up several months ago) I changed the permission to 'Send on behalf of'. The next day when I sent a test message using the account in the From: line, the target user DID NOT receive the message as "my user account on behalf of other user account" in received it as coming from "other users account" (Still the 'Send As' permission) This shows the change of permissions did not replicate or take affect. When I set up a new "send on behalf of" permission it does not work. I also set up another new "send as" on my account and it works. But when I remove the "send as" permission OR I change it to "send on behalf of" nothing changes. My test email still showing up as coming from another user ("send as") Each time I waited several minutes, refreshed the users in the EMC and exited and reloaded Outlook. Anyone have a clue what is going on???? Thanks!!

If both send on behalf and send as are set, the send as will take precedence. For your test account remove the send as permissions and try setting the user as a delegate and see if it takes affect that way instead of setting it via Exchange. Also just to verify basic Exchange settings, can you make sure inheritance is checked on these AD accounts, security tab, advanced button. Also wouldn't hurt to schedule a reboot of the Exchange server. James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

If both send on behalf and send as are set, the send as will take precedence. For your test account remove the send as permissions and try setting the user as a delegate and see if it takes affect that way instead of setting it via Exchange. Also just to verify basic Exchange settings, can you make sure inheritance is checked on these AD accounts, security tab, advanced button. Also wouldn't hurt to schedule a reboot of the Exchange server. James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com