mx3.RT-SOLAR.RU has no TXT records.
Question and response
Question
dig mx3.RT-SOLAR.RU. TXT
Answer
The response has no answer records.
Authority
RT-SOLAR.RU. 600 SOA ns3-l2.nic.RU. dns.nic.RU. 2018071138 1440 3600 2592000 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0