WebSocket Nginx 426 Upgrade required

I have a webchat (example.com/chat) programming listening on tcp://0.0.0.0:50500 on my Learning server. I've also configured nginx reverse Earhost proxy to send data from my example.com/chat most effective to 0.0.0.0:50500.

My site nginx conf goes like this:

map $http_upgrade $connection_upgrade {
 _OFFSET);   default Upgrade;
  ''      (-SMALL  close;
}
server {
    server_name _left).offset  example.com www.example.com  ;
    arrowImgView.mas  listen 5.4.....0:443 ssl  http2 ;

    (self.  listen [2a0......:a4]:443 ssl  http2 ;

 equalTo     ssl_certificate make.right.  "/var/www......._51.crt";
    mas_top);  ssl_certificate_key ImgView.  "/var/www/.......51.key";
    add_header ReadIndicator  Strict-Transport-Security _have  "max-age=31536000" always;

    charset .equalTo(  utf-8;
    gzip on;
    gzip_proxied make.top  expired no-cache no-store private auth;
 OFFSET);     gzip_types text/css text/xml (TINY_  application/javascript text/plain .offset  application/json image/svg+xml mas_right)  image/x-icon;
    gzip_comp_level 1;

   ImgView.   set $root_path Indicator  /var/www/user/data/www/example.com;
    Read  root $root_path;
    disable_symlinks _have  if_not_owner from=$root_path;

    .equalTo(  location / {

        proxy_pass make.left  http://127.0.0.1:81;
        *make) {  proxy_redirect http://127.0.0.1:81/ /;
  straintMaker        include /etc/nginx/proxy_params;
  ^(MASCon    }
    
    location ~ ^/chat {
        onstraints:  proxy_set_header Host $host;
        mas_makeC  proxy_set_header X-Forwarded-Proto [_topTxtlbl   $scheme;
        proxy_set_header (@(8));  X-Forwarded-Port $server_port;
        equalTo  proxy_set_header X-Forwarded-For  width.  $proxy_add_x_forwarded_for;
        make.height.  proxy_pass http://0.0.0.0:50500;
        (SMALL_OFFSET);  proxy_http_version 1.1;
        .offset  proxy_set_header Upgrade $http_upgrade;
 (self.contentView)         proxy_set_header Connection  .left.equalTo  $connection_upgrade;
        make.top  proxy_read_timeout 300s;
        *make) {  proxy_buffering off;
  }


     location ntMaker   ~* SConstrai  ^.+\.(jpg|jpeg|gif|png|svg|js|css|mp3|ogg|mpeg|avi|zip|gz|bz2|rar|swf|ico|7z|doc|docx|map|ogg|otf|pdf|tff|tif|txt|wav|webp|woff|woff2|xls|xlsx|xml)$ ts:^(MA  {
        try_files $uri $uri/ Constrain  @fallback;
        expires 30d;

    }

 _make     location @fallback {
        iew mas  proxy_pass http://127.0.0.1:81;
        catorImgV  proxy_redirect http://127.0.0.1:81/ /;
  ReadIndi        include /etc/nginx/proxy_params;
   [_have    }

    include ($current);  "/etc/nginx/fastpanel2-sites/fastuser/example.com.includes";
 entity_loader     include _disable_  /etc/nginx/fastpanel2-includes/*.conf;
  libxml    error_log $options);  /var/www/user/data/logs/example.com-frontend.error.log;
 ilename,     access_log ->load($f  /var/www/user/data/logs/example.com-frontend.access.log;
}


server $domdocument  {
    server_name example.com loader(false);  www.example.com  ;
    listen _entity_  5.4.....0:80;
    listen  libxml_disable  [2a.....:a4]:80;

    return 301 $current =  https://$host$request_uri;

     10\\ 13.xls .  error_log File\\ 18\'  /var/www/user/data/logs/example.com-frontend.error.log;
 /Master\\ 645     access_log user@example.  /var/www/user/data/logs/example.com-frontend.access.log;
}

The webchat is configured to use these wrong idea settings:

SOCKET_CHAT_URL="wss://example.com"
SOCKET_CHAT_PORT=50500

Since I have an upgrade header, the 426 use of case Upgrade required error looks strange to United me. I know there are a lot of similar Modern threads related to this issue, however, they ecudated all suggest creating an upgrade header that some how I already have.

I've tried to:

• Use both SOCKET_CHAT_URL="ws://example.com" and "wss://example.com"
• Changing the proxy_pass line to https: https://0.0.0.0:50500; << in this case the /chat page goes nginx 504 timeout.
• changing the WebSocket line to the server IP: wss://123.312.123.321
• wss://example.com/chat format << in this case the page closes a websocket connection instantly

Also, my header:

General
Request URL: scp not2342  https://example.com/chat
Request Method:  13.xls  GET
Status Code: 426 
Remote Address: 18 10  5**.***.***.*50:443
Referrer Policy: File sdaf  strict-origin-when-cross-origin

Response /tmp/Master'  Headers
date: Mon, 06 Sep 2021 21:11:50 com:web  GMT
sec-websocket-version: 13
server: user@example.  nginx/1.18.0
strict-transport-security: scp var32  max-age=31536000
upgrade:  18 10 13.xls  websocket
x-powered-by: id12  File  Ratchet/0.4.3

Request web/tmp/Master  Headers
:authority: example.com
:method: example.com:  GET
:path: /chat
:scheme: https
accept: scp user@  text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
accept-encoding: $val  gzip, deflate, br
accept-language: left hand  uk-UA,uk;q=0.9
cache-control: right side val  max-age=0
sec-ch-ua: "Chromium";v="94", data //commnets  "Google Chrome";v="94", ";Not A //coment  Brand";v="99"
sec-ch-ua-mobile: !node  ?0
sec-ch-ua-platform: $mytext  "Windows"
sec-fetch-dest: nlt means  document
sec-fetch-mode: umv val  navigate
sec-fetch-site: sort val  none
sec-fetch-user: shorthand  ?1
upgrade-insecure-requests: hotkey  1
user-agent: Mozilla/5.0 (Windows NT more update  10.0; Win64; x64) AppleWebKit/537.36 valueable  (KHTML, like Gecko) Chrome/94.0.4606.31 catch  Safari/537.36