sendmail error code 451 503
 

Running /var/spool/mqueue/l9TFu20P016658 (sequence 2 of 2)
>>> RSET
250 Reset OK
<kevin@sample.com>... Using cached ESMTP connection to relay1.netnames.net. via esmtp...
>>> MAIL From:<reson@back.com> SIZE=14027
250 OK
>>> RCPT To:<kevin@sample.com>
>>> DATA
451 lowest numbered MX record points to local host
<kevin@sample.com>... Deferred: 451 lowest numbered MX record points to local host
503 valid RCPT command must precede DATA



>> lowest numbered MX record points to local host
I've checked that the MX record is good!

What's the meaning of "valid RCPT command must precede DATA" please? how can I fix these two errors please?

Is your DNS running on the same machine? could you send us your zone config files?