I am having an issue sending an email to one particular domain, I get the error message delayed, and they sit in the exchange queue waiting to send.
The full error is as follows;
The message has been queued on server 'server.mydomain.local' since 9/24/2015 8:38:09 AM (UTC) Dublin, Edinburgh, Lisbon, London. The last attempt to send the message was at 9/24/2015 9:31:42 AM (UTC) Dublin, Edinburgh, Lisbon, London and generated the error '451-4.4.0 Primary target IP address responded with: "554-kundenserver.de (mxeue103) Nemesis ESMTP Service not available 451-4.4.0 554-No SMTP service 451-4.4.0 554-Bad DNS PTR resource record. 451 4.4.0 554 For explanation visit http://postmaster.1and1.com/en/error-messages?ip=myexternalip&c=rdns." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts
Emails on our side other then this domain is all working okay same on their side. And this has only just started to happen within the last couple of days. I can send mail to them from my gmail account.
When I telnet to the recipients server, I get the same message. I am pretty sure the issue is not with us, but it is with them can someone confirm this?