delivery temporarily suspended

[codezero]

I'm sending an email with the sendmail command in the shell but I get this error:
log:> mailq

77D258CC888 37750 Thu Jan 10 19:11:49 MAILER-DAEMON
(delivery temporarily suspended: connect to domain.x.com[IP]:25: Connection refused)

What should I check, I can receive and send mail, only that I do not send it from the shell or php!

[dreiggy]

Check if firewall not blocking messages.