What can cause WebSocket connection failed?

Question

Laravel

I get the following warning in the console:

WebSocket connection to 'wss://larablank:6001/app/any_key?protocol=7&client=js&version=6.0.0&flash=false' failed: WebSocket is closed before the connection is established.

I tend to believe that any_key is to blame, which I, after watching one (apparently not very useful) video on youtube, indicated instead of the real key from the pusher. But after replacing it with a real key, the address is still any_key. php artisan websockets:serve restarted, bootstrap/cache cleaned and npm run watch started. Tell me why any_key can still be substituted? Apparently because of this, the laravel-websockets monitor is not connected to the application immediately, but only after receiving

WebSocket connection to 'wss://larablank:6001/app/any_key?protocol=7&client=js&version=6.0.0&flash=false' failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED