"Reason: 553 sorry, that domain isn't in my list of
allowed rcpthosts (#5.7.1)"
This usually occurs when:
1. The domain name contained in the email address
(being sent to) has not fully propagated yet.
Domain propagation is the process where Internet
Service Providers (ISPs) around the world
automatically
update their records (DNS tables) to reflect the new
domain or to reflect a change in the hosting provider
for the domain name. Once the changes have been made,
the domain's website and email services will be
activated. Please note that full domain propagation can
take between 24-72 hours.
To verify when your domain was last
updated, we suggest that you conduct a whois on your
domain. A popular whois tool is located here: http://www.allwhois.com.
OR
2.
Your POP mail client is not configured properly. We
suggest the following: Use port 587 with SMTP
authentication or if using port 25, retrieve (POP) your
mail first before sending your messages through SMTP.
NJABL dynablock