There have been ongoing reports this week from ESPs and ISPs that AOL is having problems accepting email. People are reporting difficulties connecting to AOL MTAs and random dropping of connections. Other people are reporting random rejection messages that make no sense. A number of folks are seeing rejections claiming that the reason is a new IP when that IP has successfully sent mail from that IP in the recent past.
AOL seems to be working on things, and some people are seeing improvements. If you’re seeing AOL problems recently, it’s not you. It’s them.
EDIT: AOL has asked senders to please reduce mail volume while they are resolving issues.