Doesn't work on Cloud-Server

[marcel-se-best]

I want to run the example on Cloud-Server and cast to my local device.
In my Router I forwarded (exposed) the Chromecast-Device.
The Code connects to the public IP of my Router.

On Conecting I have the following error:
Error: read ECONNRESET
at TLSWrap.onStreamRead (node:internal/stream_base_commons:213:20) {
errno: -54,
code: 'ECONNRESET',
syscall: 'read'
}

Conecting to local IP of the Chromecast-Device, everything works fine.

Any idea?

Kind regards,
Marcel