mailgw.mexline.com has no MX records.
Question and response
Question
dig mailgw.mexline.com. MX
Answer
The response has no answer records.
Authority
mexline.com. 600 SOA ns02.mexline.com. netmin.mexline.com. 2026022501 3600 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0