I have more or less set up XEAMS. It is sitting in a VM that also hosts Exchange Server 2013 and uses the exchange servers external IP and relays to Exchange using an internal IP. I have multiple domains and these too have been added. I have completed the integration with AD and checked that this works by using a genuine user (who added) and a made up one (who was rejected). When I turn on the SMTP and Proxy services I can no longer send from Outlook, so, clearly something in the setup is amiss. It seems the easiest thing is to pass this over to your support team and pay accordingly but before I purchase support I must emphasise that I do not think this is exactly a XEAMS issue. I expect changes are needed in Exchange. Are you able to undertake both Exchange and XEAMS work if I pay for support?