Can’t send/receive email from outside.

I’m running Exchange 5.5 on an NT 4.0 server. Over the weekend we lost the ability to send/receive email outside the company. We can email internally with no problem. I’ve tried shutting down and restarting the server with no luck. I noticed in the event log that after the server comes up from a restart there is an error. The error source is: pedge. The error reads: the device \Device\Scsiport2, did not respond within the timeout period. Can anyone help me? I’m not sure what to do.

Thanks