[Plugin: Contact Form 7] Cannot send mail to addresses within our domain.

We have a simple Contact Us Form set up. When the recipient addresses are set to addresses that are not our own (i.e. Gmail) then the emails process correctly. However, when we use our own domain name (convergence-con.org) as the recipient, we are getting the following error message: “Failed to send your message. Please try later or contact the administrator by another method.”

Any suggestions on how to fix this would be greatly appreciated. Thanks.

http://wordpress.org/extend/plugins/contact-form-7/