I am battling to send mail to one specific domain.
if i try to telnet to the MX records ip and do the normal helo, mail from etc, i get the 554 SMPT sync error. (if i run the full command and dont wait for the returns from the recipient server.
if i send just the telnet xxx.xxx.xxx.xxx 25 command, and then wait till i get the response it goes further, but when i send the helo, it gives me:
220 spool.XXXXXX.com ESMTP Exim 4.69 Mon, 21 Feb 2011 09:57:36 +0200
501 Syntactically invalid HELO argument(s)"
any ideas? it seems this is the only domain that is giving me this problem?