u18980100.wl101.sendgrid.net has no NS records.
NS records for this zone are defined at wl101.sendgrid.net.
NS records for this zone are defined at wl101.sendgrid.net.
Question and response
Question
dig u18980100.wl101.sendgrid.net. NS
Answer
The response has no answer records.
Authority
wl101.sendgrid.net. 1800 SOA aisha.ns.cloudflare.com. dns.cloudflare.com. 2399128903 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0