Mail routing issue

My company has several remote sites throughout the U.S.. We have a problem where we are unable to email one of our sites. The mail gets returned in error. I don’t know the specific error yet becuase it’s in someone elses hand, but I know it’s coming down the pike to me. We have know problem emailing any of our other sites. The problem is only with this one location. I don’t think there’s any hardware connectivity issue going on. I think the problem has to do with the routing tables or something. I’m not too familiar with the route command in NT. Can some of you guys lend me your expertise on the matter so I can atleast make sure the routing is fine? Thanks….TJ