Every time I use the Message Rules for forwarding emails, I get the following error  Why???An unknown error has occurred.

Subject 'Sale Ends Sunday: Shipboard Credit, Reduced Fares & More'
Server Error: 554
Server Response: 554 Transaction failed :  Cannot send message due to possible abuse; please visit http://postmaster.yahoo.com/abuse_smtp.html for more information
Server: 'smtp.bizmail.yahoo.com'
Windows Live Mail Error ID: 0x800CCC6F
Protocol: SMTP
Port: 465
Secure(SSL): Yes

I have contacted yahoo and they say it isn't there problem.  So why do I get this error?  Thanks for your help