I have a client running SBS 2000, all service packs have been installed. I
am having a problem sending mail to one domain, att.net, all other queues
are not holding mail or nothing. If I set the exchange server to forward the
mail to the ISP mail server the att.net mail will go out but all other mail
stops working. Here is the error that the queue reports: An SMTP protocol
error occurred. Any help would be appreciated!

Thanks,
Keith