RE: AOL 421 errors

We've noticed a surge in 421 e-mail errors from AOL.

Message soft bounced for ‘###@aol.com’, ‘4.3.2 - Not
accepting messages at
this time (‘421’, [’: (DYN:T1)
http://postmaster.info.aol.com/errors/421dynt1.html’, ‘SERVICE NOT
AVAILABLE’]) []’

It seems as though they've tightened down their policies.
We're pretty good at preventing spam with our IronPort
anti-spam gateways and internal policies.

We've also subscribed to their FBL notification service.
I'm surprised at the types of messages AOL customers consider
as spam. Anything and everything: university admission acceptance
notices; instructor class assignments; photos from friends; etc.

AOL users report receipts for things they have bought or
letters from their kids as spam, or just use the spam button
instead of delete. We have a feedback loop with them on a
netblock we moved off of about 24 months ago; I've emailed
their postmaster at least 12 times with no response and no
change. I've called and they refuse to talk and say I must
email or use the form on the postmaster site to be removed;
no effect.

David