mx.gridslens.com has no NS records.
NS records for this zone are defined at gridslens.com.
NS records for this zone are defined at gridslens.com.
Question and response
Question
dig mx.gridslens.com. NS
Answer
The response has no answer records.
Authority
gridslens.com. 3600 SOA dns.gridslens.com. hostmaster.gridslens.com. 1329037719 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0