spider.conectasul.com has no MX records.
Question and response
Question
dig spider.conectasul.com. MX
Answer
The response has no answer records.
Authority
conectasul.com. 1800 SOA john.ns.cloudflare.com. dns.cloudflare.com. 2395573567 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0