Yahoo accounts issue?

[admin]

Dear Members,
For last couple of weeks all the emails sent to yahoo accounts are bouncing back with the following error.

"Technical details of permanent failure:
PERM_FAILURE: Gmail tried to deliver your message, but it was rejected by the recipient domain. The error that the other server returned was: 554 554 Message not allowed - UP Email not accepted for policy reasons. Please visit http://help.yahoo.com/help/us/mail/defe ... 4.html[120]. We recommend contacting the other email provider for further information about the cause of this error. Thanks for your continued support. (state 17)"

I don't know the reason as reported many times to Yahoo but....yet....no gain. If anyone knows the solution of this problem then please share.

Thanks