zen.r1servers.com has no MX records.
Question and response
Question
dig zen.r1servers.com. MX
Answer
The response has no answer records.
Authority
r1servers.com. 360 SOA ns1.fox.r1servers.com. office.hostbulgaria.com. 2025122407 21600 7200 1209600 360
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0