Csharp SignalR跨域

我可以看到这个问题已经被问了很多次了.然而，所有的解决方案都是老旧的，不能在DotNet 6.0上运行.

我有一个SignalR js客户.它是从服务器A呈现的.我的SignalR服务器在服务器B上.它位于固定的IP地址上.

我try 从客户端调用此服务器...

socket= new signalR.HubConnectionBuilder()
    .withUrl("http://X.X.X.X/MyHub")
    .configureLogging(signalR.LogLevel.Information)
    .build();

但我得到了错误:

错误:无法完成与服务器的协商:错误

我的服务器是ubuntu 20.Web服务器是用ASP.NET C#6.0版编写的

在服务器B中，我的程序中有:

builder.Services.AddCors(options => options.AddPolicy("CorsPolicy", policyBuilder =>
{
    policyBuilder
            .AllowAnyMethod()
            .AllowAnyHeader()
            .AllowAnyOrigin()
            .SetIsOriginAllowed(_ => true); // allow any origin 
}));

两台服务器都是HTTPS.

在我的nginx配置文件中，我有以下内容:

# Wide-open CORS config for nginx
    location / {
    if ($request_method = 'OPTIONS') {
        add_header 'Access-Control-Allow-Origin' '*';
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
#
# Custom headers and headers various browsers *should* be OK with but aren't
#
        add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
#
# Tell client that this pre-flight info is valid for 20 days
#
        add_header 'Access-Control-Max-Age' 1728000;
        add_header 'Content-Type' 'text/plain; charset=utf-8';
        add_header 'Content-Length' 0;
        return 204;
    }
    if ($request_method = 'POST') {
        add_header 'Access-Control-Allow-Origin' '*' always;
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
        add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-  Modified-Since,Cache-Control,Content-Type,Range' always;
        add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range' always;
    }
    if ($request_method = 'GET') {
        add_header 'Access-Control-Allow-Origin' '*' always;
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
        add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-        Modified-Since,Cache-Control,Content-Type,Range' always;
        add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range' always;
    }
}

我从这里得到的:

https://enable-cors.org/server_nginx.html个

upstream websocketCloud {
  server 127.0.0.1:9771;
}