Logging unsuccessful DNS queries

Hello,

is there a way of logging unsuccessfull DNS queries (a simple text log would be awesome)? We sometimes have issues with "Error: 454 4.4.4 [internal] no MX or A for domain" errors which result in messages being stuck in the queue for unneccessary long time. We suspect that the issue might be on the DNS servers we use, but we'd like to confirm this theory first.

Thanks!