C# Telegram.bot Exception (failed to create secure SSL/TLS channel)
I tried it on two servers, the result is the same.. Before that, everything worked perfectly! on the evening of 06.02, this problem appeared.. I use the dll from the repository ".NET Client for Telegram Bot API"
var me = botClient.GetMeAsync().Result;//Исключение
Console.WriteLine($"Hello, World! I am user {me.Id} and my name is {me.FirstName}.");
botClient.OnMessage += Bot_OnMessage;
2 answers
There is reason to believe that telegram has changed the set of supported cipher suites on the api server: https://www.ssllabs.com/ssltest/analyze.html?d=api.telegram.org&s=149.154.167.220&hideResults=on
In this connection, there are no supported cipher suites left on the hosts experiencing problems.
For Windows OS, you can view the cipher suite in the registry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Cryptography\Configuration\Local\SSL\00010002
The same story as on Win10, that on 2k19 it worked fine before
Yuzayu https://github.com/TelegramBots/telegram.bot and https://github.com/MihaZupan/HttpToSocks5Proxy
Found the answer here https://github.com/TelegramBots/Telegram.Bot/issues/869#issuecomment-583115520
Telegram now allows only TLS v1.2. You probably need to use this ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
After that, immediately Win10 earned but 2k19 failed to win(((