sendershub.com has no MX records.
Question and response
Question
dig sendershub.com. MX
Answer
The response has no answer records.
Authority
sendershub.com. 1800 SOA clay.ns.cloudflare.com. dns.cloudflare.com. 2395601628 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0