I have a .NET server accepting WebSocket connections and responding with whatever messages are sent. When I connect from Safari everything works as expected until I close the WebSocket and receive the following error

WebSocket connection to 'ws://localhost:8080' failed: The operation couldn’t be completed. Socket is not connected

The socket was connected and as I mentioned I was able to send and receive messages before attempting to close it. It’s readyState is OPEN before closing as well.

This is the .NET code I have

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

// Enable WebSocket support
app.UseWebSockets();

app.Urls.Add("http://localhost:8080");

app.Map("/", async context =>
{
    if (context.WebSockets.IsWebSocketRequest)
    {
        var webSocket = await context.WebSockets.AcceptWebSocketAsync();
        await Echo(webSocket);
    }
    else
    {
        context.Response.StatusCode = 400;
    }
});

app.Run();

static async Task Echo(System.Net.WebSockets.WebSocket webSocket)
{
    var buffer = new byte[1024 * 4];
    var result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);

    while (!result.CloseStatus.HasValue)
    {
        await webSocket.SendAsync(new ArraySegment<byte>(buffer, 0, result.Count), result.MessageType, result.EndOfMessage, CancellationToken.None);
        result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
    }

    await webSocket.CloseAsync(result.CloseStatus.Value, result.CloseStatusDescription, CancellationToken.None);
}

And this is the javascript code I have in the browser

ws = new WebSocket('ws://localhost:8080')
ws.send('abc')
ws.close()