Can not view new mail in Exchange 2000

Maybe you can point me to the right place, we had exchange 2000 set up and working for internal email just fine on a windows 2000 server. When we sent internet email and someone tried to reply back they got an error about permissions denied. This server is not set up as an Internet email server so we tried to fix it but now no new internal email can be view by outlook or OWA. We removed smtp by mistake but installed it back but it still does not work. I can see that the users inbox is incremented by 1 when I send them a new message in the exchange manager but it does not show up on the client end of outlook or owa.
Have you seen this before or know of someone I can past this issue to?