When you configured the machine, you didn't have it use your ISP's mail server to send messages, did you? If so, when DirectvDSL went under ( I now use Speakeasy SDSL 1.5Mbit ) if you configured that box to send to the ISP's mail server and now you've moved over to bellsouth, that could be your root cause.
I see the 4.4.2 in your case as your box trying to route outgoing messages through the DirectvDSL mail server, which probably is no long accessible, or fails because you would be "relaying" from an external host, outside their network.
Glance at your mail settings, note that there is no real benefit to using the ISP provided mailserver since your SME box can handle it with little or no problems.