Payment problem. Why doesn't the system pull callback?

Question

Payment systems

Test application: https://ok.ru/game/1244783360
Payment response: "The payment system is on prevention and will work very soon. Stay tuned!"
CallbackURL: https://ifreedocs.rankingames.com/node/test/social...
Moreover, the server logs show that it was not pulled.
Why does the system not pull him?

Answer 1

It looks like the certificate is self-signed and invalid.
A callback handshake with such a server will not work.