mx2.hc756-17.eu.iphmx.com has no CNAME records.
Question and response
Question
dig mx2.hc756-17.eu.iphmx.com. NS
Answer
The response has no answer records.
Authority
eu.iphmx.COM. 858 SOA ns1-93.akam.net. stbu-hostmaster\@cisco.COM. 1771961172 3600 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0