u15526930.wl181.sendgrid.net has no NS records.
NS records for this zone are defined at wl181.sendgrid.net.
NS records for this zone are defined at wl181.sendgrid.net.
Question and response
Question
dig u15526930.wl181.sendgrid.net. NS
Answer
The response has no answer records.
Authority
wl181.sendgrid.net. 1800 SOA aisha.ns.cloudflare.com. dns.cloudflare.com. 2399278829 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0