Custom scripts cant work

Please advise.

I get this error when running a custom script.

socketio_client.js:56 WebSocket connection to ‘ws://localhost:8080/socket.io/?EIO=4&transport=websocket&sid=yKUz_bbxi4PgZ9tGAAAK’ failed: WebSocket is closed before the connection is established.

is this an error in my script? Or in fact an issue on my local docker server blocking any custom scripts I would attempt?

Does your custom app have an associated web application?

I have very limited knowledge, so excuse my ignorance.
my aim for now is to run client scripts within erp next.
I have no custom apps running. my system as is:

windows 10
running docker with local frappe server and erp next installed.

when I try to run basic client scripts they do not work.
in my browser web it complains that the web socket disconnects.

what is my prerequisites required to have client scripts enabled?