[cobalt-users] MX Records pointing to mailrecv.bigmailbox.com? NOT WORKING?

["Clint Decker" <nim1998@xxxxxxx>]

I use an external mail service called BigMailBox.com to provide free web
based email for customers, im sure some of you have heard of it...

Well anyways.. the instructions to set this up say to point the mx records
to mailrecv.bigmailbox.com,... so my settings look like this:

hackersunderground.com      64.39.236.167
 www.hackersunderground.com      64.39.236.167
 64.39.236.167/28      hackersunderground.com
 hackersunderground.com   mail is sent to the Very-High priority mail server
mailrecv.bigmailbox.com

When I send a test message from an outside server  (from a domain or server
that is NOT setup on my raq3) the email gets delivered.  When I send the
message from a domain which IS setup on my raq3 (on the same server as
hackersundergroud.com) (menaing im using the mail server ON the raq3, i get
an error saying "Server Response 550 louish@xxxxxxxxxxxxxxxxxxxxxx user
unknown )

Does anyone know why this is happening?  I can send mail to anyone who uses
this external mail server, I always get errors?!

Thanks,
Clint Decker