4.5.1 4.4.0 DNS Query Failed
- by Justin
We are running Exchange 2010 and lately I have noticed that some outgoing messages get stuck in the queue with the error "451 4.4.0 DNS Query Failed". On every domain that this happens on I have been able to use nslookup to find the MX record and open a connection to their server over SMTP so I am reasonably sure that this problem is on my end. My send connector isn't routing mail through a smart host nor is is set to use a different DNS server to do the lookup so I'm stumped as to why these messages aren't going out. Any ideas?