UNET and WebGL: ERR_CONNECTION_REFUSED

I have a project which works fine as a standalone application (client connects to server without issues).
When I build it for WebGL, deploy and run it, I get the following error when I try to connect to the server:

WebSocket connection to 'ws://127.0.0.1:19019/' failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED
/ll/Release/ll.js:1 Error: undefined socket will be closed


The server is set to NetworkServer.useWebSockets = true; but it's the same error even if the server...

UNET and WebGL: ERR_CONNECTION_REFUSED