smtp2.iriscrm.com has no NS records.
NS records for this zone are defined at iriscrm.com.
NS records for this zone are defined at iriscrm.com.
Question and response
Question
dig smtp2.iriscrm.com. NS
Answer
The response has no answer records.
Authority
iriscrm.com. 3600 SOA ns-379.awsdns-47.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0