I have been trying to troubleshoot an ERP issue where we cannot send an alert outside of the network. Outlook works fine (in house Exchange server), and we are sending and receiving email fine. The ERP has a domain user and password to connect to exchange with (The server rejected one or more recipient addresses. The server response was: 550 5.7.1 Unable to relay). When I connect with Telnet, it accepts my domain username, but fails when I try to send to anyone outside the internet for the recipient with Unable to Relay.
We have not had any issues with email via OWA or Outlook, so this is new for me to troubleshoot.
We are not running TLS.
Any suggestions would be helpful! Thanks