I have a .NET developed .EXE application which runs as scheduled task from command line. It uses System.Net.Mail with client.Host = "127.0.0.1". It ran fine on a Server 2012, sending to both local and remote addresses. When we migrated to a different Server 2012, only those addressed to local accounts were sent. Local connections using Telnet work as expected. The ME Ver 8.58 SMTP logs show no connection attempts on the new server when the .EXE application runs, making me think it might be "upstream" between the .NET environment and ME.
I am running out of ideas. Anybody?