mtallm01.ihotelier.com has no MX records.
Question and response
Question
dig mtallm01.ihotelier.com. MX
Answer
The response has no answer records.
Authority
ihotelier.com. 7200 SOA a2-66.akam.net. hostmaster.ihotelier.com. 2015112825 10800 600 604800 7200
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0