We have an on-premises Exchange 2019 server with a subscribed Edge Transport server.
This is working fine.
I now need to allow an external Exchange server to use us as a relay to send external mails. This server is not part of our Exchange organization or AD domain, but we trust it sufficiently to implement this requirement.
I have added a new FrontEndTransport Receive Connector on our Exchange server, configured it for Anonymous access and set the Scoping to only accept email from the IP address of the remote Exchange server. I have also deselected all authentication mechanisms for the connector - i'm not sure if that's correct.
Unfortunately when I send mails from the external server I keep getting NDRs along the lines of: [FQDN on Edge server] #550 5.7.54 SMTP; Unable to relay recipient in non-accepted domain ##
I have made sure that the Edge Subscription is synchronized but the problem persists.
Some picture of my configuration:
![81138-image.png][2] ![81187-image.png][3]
Any hints would be nice?
Best Regards John B


