ns1.systemdns.com has no NS records.
NS records for this zone are defined at systemdns.com.
NS records for this zone are defined at systemdns.com.
Question and response
Question
dig ns1.systemdns.com. NS
Answer
The response has no answer records.
Authority
systemdns.com. 300 SOA ns1.tucows.com. hostmaster.systemdns.com. 1771859465 10800 3600 2592000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0