have you followed the advice in
http://help.yahoo.com/help/us/mail/defer/defer-01.html
-- especially the bit about reading the full error text of
any failure SMTP responses you've had in previous queue
runs? Have you talked to the Yahoo email people? (IME
they're generally helpful-sounding but most of the
policies seem to be nonnegotiable, even simple ones like
`can you support a postmaster address?'.) Are you by any
chance trying to forward mail?
--
``I dissect fruit fly heads for a living.
How hard can kneecapping a mouse be?''
(pest-control solutions, as seen on the internet)
