AOL mail delivery delayed (resolved)
Update 6:20 PM October 11: AOL has resolved the problem described below. All delayed mail has been delivered, and all services are operating normally.
Original post: We’ve noticed today (October 10, 2012) that the aol.com mail servers are delaying some of the mail our servers are sending to them.
This appears to be a problem on their end — we don’t believe this is directly related to us, because their IP address reputation checker says that all our servers have a “good reputation”, and that we “should not be experiencing bounce or reject errors when sending mail from this IP”. In addition, their servers are replying with generic “421 Service unavailable – try again later” messages, instead of any of their documented errors.
However, we’ve opened a ticket with them, and we’ll update this post when we either receive a reply or when they accept the backlog of queued mail from our servers.