mc55.fra.server.colt.net has no CNAME records.
Question and response
Question
dig mc55.fra.server.colt.net. NS
Answer
The response has no answer records.
Authority
server.colt.net. 3558 SOA ns20.colt.net. eudnsmaster.colt.net. 2013053135 10800 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0