sendgrid.mspmanager.com has no NS records.
NS records for this zone are defined at mspmanager.com.
NS records for this zone are defined at mspmanager.com.
Question and response
Question
dig sendgrid.mspmanager.com. NS
Answer
The response has no answer records.
Authority
mspmanager.com. 900 SOA ns-1128.awsdns-13.org. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0