I have two servers, both using ISPConfig 3 running on Ubuntu 10.04. I follow the guide (Perfect Server...). Both servers seem to work fine. I have web, ssh, ftp, etc. But on one is unable to send mail messages. The output of mailq is: E449B22087B 494 Tue Jan 22 11:13:25 email@example.com (host 127.0.0.1[127.0.0.1] said: 451 4.5.0 From MTA([127.0.0.1]:10025) during fwd-connect (Negative greeting: at (eval 113) line 596, <GEN35> line 105.): id=00921-03 (in reply to end of DATA command)) firstname.lastname@example.org Help please!!!