mx2.cvent-planner.com has no NS records.
NS records for this zone are defined at cvent-planner.com.
NS records for this zone are defined at cvent-planner.com.
Question and response
Question
dig pr51-mxa-nlb-3b0a86b0084c3e1b.elb.us-west-2.amazonaws.com. NS
Answer
The response has no answer records.
Authority
elb.us-west-2.amazonaws.com. 60 SOA ns-1870.awsdns-41.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 60
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0