Looks like they've finally completely blocked off their abuse mailboxes.
----- The following addresses had permanent fatal errors -----
<ab...@yahoo.fr>
(reason: 554 Message not allowed - [298])
----- Transcript of session follows -----
... while talking to mx-eu.mail.am0.yahoodns.net.:
DATA
<<< 554 Message not allowed - [298] 554 5.0.0 Service unavailable -Dan
