mail3.memset.com has no NS records.
NS records for this zone are defined at memset.com.
NS records for this zone are defined at memset.com.
Question and response
Question
dig mail3.memset.com. NS
Answer
The response has no answer records.
Authority
memset.com. 2560 SOA ns1.memset.com. hostmaster.memset.com. 1771790415 16384 2048 1048576 2560
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0