Can not established Websocket secure connection on Firefox

Question

I am stucked with Firefox. I could not make Websocket work on it. I use Tornado Websocket and I initialized it by code below:

app = Application([(r'/mypath/ws', WSHandler)])
http_server = HTTPServer(app, ssl_options={
                "certfile": "~/certs/websocket.crt",
                "keyfile": "~/certs/websocket.key"
            })
http_server.listen("443")

And I initialized it on Javascript side like this:

var WS = new WebSocket("wss://websocket.localhost/mypath/ws");

This code works fine on Chrome, meanwhile I created the cert by myself and run the page under HTTPS. But Firefox keeps saying that:

Firefox can't establish a connection to the server at wss://websocket.localhost/mypath/ws.

I google it and found too many thoughts but none of'em worked for me :(

Any help will be appreciated.