Bulk email

Please help me. I’m using Outlook Express and I can’t send some of my emails because it bounced back as Unsolicited Bulk Email. I’m on IMAP configuration.

I tested copying the email the I want to reply on (which consists of several replies) to a new one and surprisingly it worked. But I don’t understand why this is happening!

Does anybody had the same experience that I have or at least saw how to repair this problem? I already googled it but nothing worked so far. Even tips from Microsoft didn’t work. There’s still one last thing I haven’t tried though and its re-installing the IE (because its packed together with outlook express). Any sugestions would be very much appreciated.