Exchange Server 5.5 Queues

I seem to be havin a prob in that no mail seems to be transferred between the Exch Server sites. I get a reply when pinging both ways and the leased line is up …. seems to be more of a network bandwidth problem. Therefore the mail jus queues but is not sent. Now in Event Viewer I do get a message saying that the redirector service could not locate the specified server!!
It has happened before and seemed to sort itself out …. is there any other solution?? Please help!!!
Thanx