dns2.iplanisp.com has no CNAME records.
Question and response
Question
dig dns2.iplanisp.com. NS
Answer
The response has no answer records.
Authority
iplanisp.com. 823 SOA dns1.iplanisp.com.ar. hostmaster.iplan.com.ar. 2018122808 3600 600 1400000 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0