Why does an error occur when visiting the site https://core.telegram.org: "An error occurred while establishing a secure connection"?

Question

Debian

There is debian9 with firefox 60. when I go to the site I write an error

Error establishing a secure connection

I pull curl:

curl https://core.telegram.org/ --verbose
*   Trying 5.3.3.17...
* TCP_NODELAY set
* Connected to core.telegram.org (5.3.3.17) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: /etc/ssl/certs
* TLSv1.2 (OUT), TLS header, Certificate Status (22):
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* Unknown SSL protocol error in connection to core.telegram.org:443 
* Curl_http_done: called premature == 1
* stopped the pause stream!
* Closing connection 0
curl: (35) Unknown SSL protocol error in connection to core.telegram.org:443

I connect to openvpn I go to the site writes an error:

An error occurred while connecting to core.telegram.org. SSL received a record that is longer than the maximum allowed. Error Code: SSL_ERROR_RX_RECORD_TOO_LONG

I pull curl:

*   Trying 5.3.3.17...
* TCP_NODELAY set
* Connected to core.telegram.org (5.3.3.17) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: /etc/ssl/certs
* TLSv1.2 (OUT), TLS header, Certificate Status (22):
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol
* Curl_http_done: called premature == 1
* stopped the pause stream!
* Closing connection 0
curl: (35) error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol

Chromium does not enter the printsepe either, I think that maybe what libraries did not deliver?
openssl version OpenSSL 1.1.0j 20 Nov 2018
ca-certificates package is installed with the newest version (20161130+nmu1+deb9u1).
On Windows in the same network, when connecting to openvpn, it enters the site normally.

Answer 1

core.telegram.org banned by RKN. Connecting to it from the territory of the Russian Federation only through vpn or proxy.