Forwarding mail with mx

[IWSTechHead]

Using webmin I've created a domain master zone in BIND with an mx record that SHOULD forward mail from one domain to an exchange server hosted on another ip/domain. When I send an email to the domain that should be forwarding I get

(Name server: mail.(theexchangeserver).com.(thedomainthatshouldb eforwarding).com.: host not found)

I created the domain master zone in BIND which includes everything I THINK I need.

In sendmail, just in case, I created a virtuser that forwards all mail to the initial domain to the exchange server. This doesn't seem correct if I'm not hosting the mail.

Any help would be much appreciated.

[IWSTechHead]

I've updated the mx record to point the mail in the right direction, deleted the virtuser entries.

Though now I recieve

"553 5.3.5 (thedomain).com. config error: mail loops back to me (MX problem?)"
554 5.3.5 Local configuration error