How correctly in Nginx to be proxied to another WebSocket's port?

There is an application on the server, listening to port 7777 and waiting for a ws: // connection

Briefly about how it should work: Browser -> Nginx (HTTPS) -> WS Server (here we want not to use the certificate, which is why such problems)

The problem is that for some reason, when sending data to the server, only part of the messages from JS arrive:

Always comes 1 letter from the message, which is very strange. I tried to run all the same on the local Windows machine, everything works as it should.

Launched on c # using websocket-sharp

WebSocketServer srv = new WebSocketServer(7777); srv.AddWebSocketService<MyClient>("/ws");//сюда должен перенаправлять proxy_pass srv.Start(); Console.WriteLine("Server is listening......"); //простой listener с выводом данных class MyClient : WebSocketBehavior { protected override void OnOpen() { Write("Client Connected!", ConsoleColor.Green); } protected override void OnClose(CloseEventArgs e) { Write("Close connection: "+ e.Reason, ConsoleColor.Red); } protected override void OnError(ErrorEventArgs e) { Write("Error: "+e.Message, ConsoleColor.DarkRed, ConsoleColor.Gray); } protected override void OnMessage(MessageEventArgs e) { Write(e.Data); } } 

Simple JS client:

 var socket = new WebSocket("wss://мой-сайт/Game"); socket.onopen = function() { console.log("Соединение установлено."); activeBtns(false); }; socket.onclose = function(event) { if (event.wasClean) { console.log('Соединение закрыто чисто'); } else { console.log('Обрыв соединения'); // например, "убит" процесс сервера } console.log('Код: ' + event.code + ' причина: ' + event.reason); activeBtns(true); }; socket.onmessage = function(event) { console.log("Получены данные "); console.log(event.data); }; socket.onerror = function(error) { console.log("Ошибка " + error.message); activeBtns(true); }; activeBtns(); sendData = function(){ socket.send("test message"); }; 

On the server (OS: Ubuntu) there is Nginx with settings (installed clean v1.14.1):

 user www-data; worker_processes auto; pid /run/nginx.pid; include /etc/nginx/modules-enabled/*.conf; events { worker_connections 768; # multi_accept on; } http { sendfile on; keepalive_timeout 604800; proxy_connect_timeout 604800; proxy_send_timeout 604800; proxy_read_timeout 604800; include /etc/nginx/mime.types; default_type application/octet-stream; access_log /var/log/nginx/access.log; error_log /var/log/nginx/error.log; include /etc/nginx/conf.d/*.conf; include /etc/nginx/sites-enabled/*; } #конфиг моего домена: server { listen 443 ssl; server_name мой-сайт; #тут мой домен access_log /etc/nginx/logs/log.access; error_log /etc/nginx/logs/log.error error; ssl on; ssl_certificate /etc/ssl/certs/cert.pem; ssl_certificate_key /etc/ssl/private/cert.key; client_max_body_size 1M; client_body_buffer_size 1M; location / { root /var/www/мой-сайт/html; index index.html index.htm; } location /Game { proxy_pass http://мой-сайт:7777/ws; proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection "upgrade"; } } 

Perhaps there are some other settings that can be changed?