Postfix not sending mail out

Wed Nov 7 20:18:09 UTC 2007

After being away from Redhat for some time, I just installed a server 
with postfix--2.4.3-2.fc7. It receives mail ok, but when I try to send 
mail, it stays in the queue with this error: 

(Host or domain name not found. Name service error for 
name=fusionalliance.com type=MX: Host not found, try again) 

However I can do a host -t MX and find the data for the fusionalliance.
com mail servers.

Does anyone have an idea why my mail is staying queued?

Vicki