Believe that's something to do with our operation.
When I put the box in stand-by (switching-off from remote) and again switching it on, YouTube won't play (freezes after playing less than a second), same happens with Prime video but not with any other apps.
The other time it happens when there's a drop in network (switching hotspot device is fine).
Whatever you do, it won't work unless you power it off and switch on again.