[CentOS] postfix help. im clueless

Hi, I have been given the task to check on a postfix server that presents the following error: Let's say you use your hotmail account and then send a message to one of my users. The postfix program running on the server responds:

Jun 4 10:21:25 mail postfix/smtp[29744]: 553E01079AD: to=email.elpanama@elpanama.com, relay=localhost[127.0.0.1], delay=54253, status=deferred (host localhost[127.0.0.1] said: 451 Unable to complete command, DNS not available or timed out (in reply to MAIL FROM command))

first, why is giving me a timeout? and second, why in the response the to= field has the domain name?

what things can i see in the main.cf?