If you are seeing a DNS:NR error when you attempt to connect to AOL's mx record, we are refusing your connection because the server you are using to send email has no reverse-DNS, or pointer record associated with the IP.
We have been refusing emails from servers with no reverse DNS for years, so this is nothing new. However, the mechanism we were using until recently still allowed a trickle from those servers through.
We recently fixed the glitch, so you may find your emails are now entirely refused, rather than trickling through at a very slow rate.
For those senders who have opened tickets with our Postmaster team and have updated their pointer records accordingly (and who now have reverse-DNS), based on how our lists are aggregated/pushed into production, you may see a 24 - 36 hour delay between when your DNS configurations are updated, and when you are successfully sending emails again to our system.