nsblock1.webmastercolombia.net has no CNAME records.
Question and response
Question
dig nsblock1.webmastercolombia.net. NS
Answer
The response has no answer records.
Authority
webmastercolombia.net. 541 SOA ns1.webmastercolombia.net. root.webmastercolombia.net. 54511 43200 900 1814400 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0