mail.eventact.com has no NS records.
NS records for this zone are defined at eventact.com.
NS records for this zone are defined at eventact.com.
Question and response
Question
dig mail.eventact.com. NS
Answer
The response has no answer records.
Authority
eventact.com. 300 SOA ns-cloud-e1.googledomains.com. cloud-dns-hostmaster.google.com. 1 21600 3600 259200 300
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0