Error in EnabledSslProtocols Tls13

[clobotorre]

Hi.

I have correctly running a running a fleck websocket using Tls12:

server = new Fleck.WebSocketServer("wss://0.0.0.0:" + _wsPort.ToString());
X509Certificate2 certificate = new X509Certificate2(_certFilePath);
if (certificate != null)
            {
                server.Certificate = certificate;
                server.EnabledSslProtocols = System.Security.Authentication.SslProtocols.Tls12; 
            }
server.Start(...

In my client application, I have this JS websocket connection related piece of code:

let socket = new WebSocket('wss://localhost.local:9999');

With Tls12 the above code is working with no problems. If I change server.EnabledSslProtocols to Tls13, Chrome complaints with "WebSocket connection to 'wss://localhost.local:9999/' failed:"

Is Tls13 supported on Fleck? If so, Is there anything special to be done with the certificate i am using, and which is working on Tls12?

Thanks

[statianzo]

Nothing special is needed as far as I know.

If you navigate your browser directly to https://localhost.local:9999 does chrome give you more details on the error?

have you tried any other browsers?

What OS and .net version?

[clobotorre]

If you navigate your browser directly to https://localhost.local:9999 does chrome give you more details on the error?

ERR_TIMED_OUT

have you tried any other browsers?

Yes, same result.
It is as if the requests are not reaching the websocket when I use TLS 1.3

What OS and .net version?
Windows 10 Pro (21H1)
.NET Framework 4.8

Is there a way to debug what is going on inside Fleck's websocket, just to be sure requests are one way or another reaching the websocket using TLS 1.3 and, f so, what happened with those requests?

[statianzo]

Setting FleckLog.level = LogLevel.Debug will output more verbose details about what's happening from Fleck's point of view.

[StevenBonePgh]

Are you sure that the client is attempting to negotiate TLS 1.3? A network trace may help determine this. If a proxy is involved this is known to be problematic. There is quite a mess with TLS 1.3 as the framework and OS are both involved, and I don't know how to help here, other than to say I have not tried TLS 1.3 yet myself, and unfortunately won't have the bandwidth to do so in the next few days.

As an aside, when setting the server.EnabledSslProtocols you can OR them if you want to accept more than one version of TLS:
server.EnabledSslProtocols = SslProtocols.Tls12 | SslProtocols.Tls13;