The LED on the remote control usually lights up white when you press a button.
The TV-Box is not within range of the remote control. Move closer to the TV-Box.
The TV-Box does not have power. Check if the TV-Box is plugged into a socket.
The TV-Box needs to be rebooted for technical reasons. Reboot the TV-Box.
Use your smartphone as a remote control with the TV Air app remote control function. You can find the remote control under "Home", at the top right.