How to create the wss://my.domain/xmpp-websocket endpoint?

I think the default installation does not install any xmpp-websocket endpoint in the nginx virtual host file, and i can see in the browser “connection closed” on these requests to /xmpp-websocket after indicated in config that the preferred channel type is websocket.
Please advise on how to create this endpoint on the server,

Also, is the automatic reconnection feature in case of websocket channel disconnect, available in the latest release 2.1-273 i think? (the connections are desktop so should be ok though)
Thank you