Larry G. Wapnitsky: > 220 mailproc.domain.com ESMTP Postfix (Debian/GNU) > helo test > 250 mailproc.domain.com > mail from: root > 451 4.7.1 Service unavailable - try again later
This mail server error message is intentionally obscure. It would be a bad idea to give out detailed internal error information via the SMTP port. To get the details of what is wrong you need to look for warning messages in the maillog file. See for example http://www.postfix.org/DEBUG_README.html#logging Wietse
