yandex.ru/MX: No response was received until the UDP payload size was decreased, indicating that the server might be attempting to send a payload that exceeds the path maximum transmission unit (PMTU) size. See RFC 6891, Sec. 6.2.6. (2a02:6b8:0:1::1, UDP_-_EDNS0_4096_D_KN)
yandex.ru/SOA: No response was received from the server over UDP (tried 6 times) until the COOKIE EDNS option was removed (however, this server appeared to respond legitimately to other queries with the COOKIE EDNS option present). See RFC 6891, Sec. 6.1.2. (2a02:6b8::1, UDP_-_EDNS0_4096_D_KN_0x20)