ns3.nextlayer.com has no MX records.
Question and response
Question
dig ns3.nextlayer.com. MX
Answer
The response has no answer records.
Authority
nextlayer.com. 86400 SOA ns.nextlayer.at. hostmaster.nextlayer.at. 2026012904 10800 900 604800 86400
Additional
. 0 OPT ; payload 1400, xrcode 0, version 0, flags 0