recipient problem in exchange 5.5

[mbeaver]

had to do a server rebuid (nt4). Re-installed exchange server 5.5
Users can send internally and can receive external emails but as soon as they try and email externally (using outlook 2000)the system administrator returns the email as undeliverable due to recipient name not recognised (event id 209).
Have checked the settings and am stumped.
They use smtp, forward email to is set to smtp server in IMS.

 

[Invincible]

Try deleting and recreating the e-mail profile to the Exchange server on the client side.

 

[Guest_imported]

What component is generating the NDR? Last line of NDR should say. If it's the MTA, make sure you have an asterisk on Address Space tab of IMS, not your own domain name.