mx2.bitrixsoft.com has no NS records.
NS records for this zone are defined at bitrixsoft.com.
NS records for this zone are defined at bitrixsoft.com.
Question and response
Question
dig mx2.bitrixsoft.com. NS
Answer
The response has no answer records.
Authority
bitrixsoft.com. 900 SOA ns-993.awsdns-60.net. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0