ns2.layer3.ng has no MX records.
Question and response
Question
dig ns2.layer3.ng. MX
Answer
The response has no answer records.
Authority
layer3.ng. 1800 SOA alaric.ns.cloudflare.com. dns.cloudflare.com. 2396808508 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0