Why is my mail being bounced?

Several people have advised me that email to my minipaws2@yahoo addy is being bounced. The error message states: "The error that the other server returned was: 554 554 delivery error: dd this user doesn't have a yahoo.com account. (minipaws2@yahoo.com) [0] - mta1068.mail.ac4.yahoo.com (state 18) ?????????????????????