Hello @florin.hebean 

Is the Android box connected to the router viia a cable? Does it help úsing another LAN port?

Yes, it is connected via a cable. What is strange, when the Android Box is ON everything is working fine. The internet is dropping down only when the android box is OFF.

@florin.hebean

Does using another LAN port help or is the box connected to a switch? You could try a direct connection than.

And when the box turns off WiFi and wired devices loses connection? Does the globe turn red or does it remain green?

The box is connected via an internet socket to the switch. When the box turns off WiFI and wired devices loses connections and the globe (Internet) turn red.

@florin.hebean 

Maybe test after performing a factory reset of the router by pressing the reset button behind the router for about 10 seconds using a small object?

I tested, it is the same.

@florin.hebean 

Are you able to connect the tv box directly to the router and test?

I will do it this afternoon. Thanks for advice.