ns2.simply.com has no MX records.
Question and response
Question
dig ns2.simply.com. MX
Answer
The response has no answer records.
Authority
simply.com. 3600 SOA ns1.simply.com. hostmaster.simply.com. 2026022000 14400 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0