u18370640.wl141.sendgrid.net has no NS records.
NS records for this zone are defined at wl141.sendgrid.net.
NS records for this zone are defined at wl141.sendgrid.net.
Question and response
Question
dig u18370640.wl141.sendgrid.net. NS
Answer
The response has no answer records.
Authority
wl141.sendgrid.net. 1800 SOA aisha.ns.cloudflare.com. dns.cloudflare.com. 2399186678 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0