rev.globalcollect.com has no MX records.
Question and response
Question
dig rev.globalcollect.com. MX
Answer
The response has no answer records.
Authority
rev.globalcollect.com. 60 SOA dns1.p08.nsone.net. hostmaster.nsone.net. 1637585919 7200 1800 2419200 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0