cp1.securelinknet.com has no MX records.
Question and response
Question
dig cp1.securelinknet.com. MX
Answer
The response has no answer records.
Authority
securelinknet.com. 1800 SOA arnold.ns.cloudflare.com. dns.cloudflare.com. 2395902141 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0