unknown.dal.cologlobal.com has no MX records.
Question and response
Question
dig unknown.dal.cologlobal.com. MX
Answer
The response has no answer records.
Authority
cologlobal.com. 1800 SOA ajay.ns.cloudflare.com. dns.cloudflare.com. 2392786828 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0