Here is some more info which I hope helps.
I ran nslookup, the the following commands:
ls -t MX mycompanyname.org (to check for a Mail Exchange record)
ls -t A mycompanyname.org (to check for a Host record)
Both command returned the following result:
"can't list the domain mycompanyname.org: Query refused"
> The Exchange 5.5 mailboxes are in an NT4.0 domain. The Exchange 2000
> mailbox is in a Windows 2000 domain with Active Directory set up. We are
> not hosting our DNS connection. We have a WAN connection and WAN IP
> to where our DNS is being hosted. Finally, as far as I can tell we have
> firewall set up between us and our WAN connection. I hope this helps.
> Thanks Again,
> > What is your network setup? You say 2 domains, so your Exchange 5.5 box
> > in a Windows 2000 environment or not? More specifics, DNS info,
> > WAN connection, etc. Need a little more info
> > --
> > John Oliver, Jr.
> > MCSE, MCT, CCNA, Exchange MVP
> > > Hello:
> > > I have a new mail server in a new domain I am testing. I am to the
> > > where I can send email internally (to my old mail server in my current
> > > domain) but I cannot receive email internally. Also, when I try to
> > > email to an external domains I get the following message;
> > > "There was a SMTP communications problem with the recipient's mail
> > > Please contact your system administrator.
> > > <mail_server.comapnyname.com #5.5.0smtp;550 Relaying is prohibited>
> > > The new mail server is an W2K Server / E2K configuration and the old
> > > server is a NT4.0 Server / Ex5.5 configuration. I have tried a lot of
> > > different ways to resolve this issue, but nothing has worked. Any
> > will
> > > be greatly appreciated.
> > > Thank you,
> > > Bill