I configured Relay MTA for external delivery: 18.104.22.168 : 25 to send mail from local user to yahoo or gmail. And this is Mail Delivery System and recive back when sending:
The mail system
<email@example.com>: host 22.214.171.124[126.96.36.199] said: 550
firstname.lastname@example.org must check for new mail first (in reply to MAIL
Please tell me why and how to correct!