Thanks Peter and Melvin for your suggestions. The two subscribers Melvin mentioned Hofnews and IGC.APC.Org are indeed redistribution lists and may be the source of the problem. I have my list of subscriber's with the .CA extension. I haven't received any errors for the past few hours so perhaps it is over. If not I'll follow Peter's strategy and try and track the Canadians. But maybe it was an April Fools joke. Not funny however. Eleftheria Maratos-Flier