mx.ttbayi.com.tr has no NS records.
NS records for this zone are defined at ttbayi.com.tr.
NS records for this zone are defined at ttbayi.com.tr.
Question and response
Question
dig mx.ttbayi.com.tr. NS
Answer
The response has no answer records.
Authority
ttbayi.com.tr. 300 SOA ns1.ttidc.com.tr. idcteam.turktelekom.com.tr. 2014070714 21600 14400 3628800 604800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0