Emails being wrongly delivered after DNS change

[Stuart]

Hi,

We recently setup a new domain on our server with email accounts, it
was decided that the owner of the domain would rather use Google Mail
to host their company email accounts. I have changed the DNS MX
records in the db.domain.com file to reflect that of Google's and
email is working fine.

The problem lies with emails that originate from the server such as
contact forms, when these are used they deliver the emails to the POP
account on the server, if I delete the account on the server and use
the contact form, the emails don't go anywhere.

For some reason apache? is sending the emails to local mailboxes
rather than to the external MX servers, is
there any other setting I need to change?

Thanks.