mx.spd.net.tr has no CNAME records.
Question and response
Question
dig mx.spd.net.tr. NS
Answer
The response has no answer records.
Authority
spd.net.tr. 3546 SOA win-vocr138f1a9. hostmaster. 2026022601 900 600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0