mx.ttbayi.com.tr has no MX records.
Question and response
Question
dig mx.ttbayi.com.tr. MX
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