Outbox in Office 2000

My system got outlook 2000 on there and it is connected to Exchange 5.5. The problem is that when the person tries to sent an e-mail, the e-mail will get stuck in outbox but the the e-mail is actually got sented. I was just wondering why is it happening and how do i fix that because at the moment i can’t tell if the e-mail is actually being sent or not. Thanks