spf314.gca.su has no MX records.
Question and response
Question
dig spf314.gca.su. MX
Answer
The response has no answer records.
Authority
gca.su. 3600 SOA ns-mail02.getcourse.ru. hostmaster.gca.su. 1452 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0