I've cheked the browser's console and spotted these.

Running on Google Chrome but i tested on opera GX as well and got the same error.

Server Settings

I don't know if it helps, but i'm using these settings for build.

Nothing more was changed.

Locally everything runs as it's supposed to but when i build and deploy the game files to my http server (firebase hosting) this happens.

(sorry my bad english)

@coco Solved! Thank you!

Is there a way to prevent users from creating rooms? I'm asking because on my game, rooms are created only by server-side, users are only allowed to join, so i'm trying to prevent possible hackers from do it.

(sorry my english)