Had this happen...had to connect a keyboard to box, use that to turn volume back on. Remote wouldn’t fix issue..
Press the right arrow key while watching tv with full screen.
Do you have the epg for these polish chanels?
The emulator thinks your volume is muted. Use the firestick remote app and use the right arrow or the regular firestick remote and use the right arrow to turn the onscreen volume control all the way up or simply once just to take off mute.
You're on mute, turn your volume up.