Original Title: Error 554 5.5.1. Advise please.I have been using Outlook 2003/XP Professional since a few years now and had no problem in receiving/sending my messages. Recently I installed a new PC with WIN7/Prof. and reinstalled the Office 2003. I receive my messages. But my sent messages are stopped by System Administrator though I am a sigleuser/owner. I get the Error 554 5.5.1. Advise please.