ns3.metrooptic.com has no MX records.
Question and response
Question
dig ns3.metrooptic.com. MX
Answer
The response has no answer records.
Authority
metrooptic.com. 600 SOA ns1.metrooptic.com. root.metrooptic.com. 2025122502 600 300 3024000 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0