We recently switched ISPs and started having issues with email going out to certain domains. It will just sit in queue. an SMTPdiag /v on these domaines show the following.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to mailin-02.mx.aol.com.
Connecting to mailin-01.mx.aol.com [18.104.22.168] on port 25.
Connecting to the server failed. Error: 10060
Failed to submit mail to mailin-01.mx.aol.com.
Everything I have found online referes to a reverse DNS issue, I have repeadadly verified that our DNS records are setup properly with the new ISP. Does anyone have any other suggestions what it could be?