Sendmail help

[Carl Parrish]

HELP,
I'm trying to set up sendmail using Webmin. I set the local host to 
myDomain.com in the local domain (cw) file. Adding myDomain.com to my 
DNS server that seems to work because going http://www.myDomain.com gets 
me the website on the server. But if I try to send mail to 
cparrish@myDomain.com I get the following error.

Reason:    sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)

What am I doing wrong. / what did I miss?