I have 2 TV boxes.
One of them, model IP 1800 works fine.
The other, model IP 2000, seems to disconnect after 30 minutes, the screen just goes grey. If I then switch the box off and on again it works fine for another 30 minutes.
The TV box that fails is connected to an old TV with SCART inputs via a SCART to HDMI converter. Not sure if this is relevant.