I have a ticket system with it's own user account on the network. It's does not have a mailbox attached to it. When I use this account to send mail through our SMTP server (exchnage) it will not send and I get the follwing message:
Failed to send data [SMTP: Invalid response code received from server (code: 550, response: 5.7.1 Client does not have permissions to send as this sender)]
Does it need a mailbox?