Sendmail help

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?