bolivia191.tigo.com.bo has no NS records.
NS records for this zone are defined at tigo.com.bo.
NS records for this zone are defined at tigo.com.bo.
Question and response
Question
dig bolivia191.velcrodigital.com. NS
Answer
The response has no answer records.
Authority
com. 900 SOA a.gtld-servers.net. nstld.verisign-grs.com. 1773947776 1800 900 604800 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0