My NVidia Shield won't show on my new QN90A

[MungoBBQ]

So I've just got my brand new QN90A, and I'm new to Samsung TVs. I have an NVidia Shield, and it shows up when I connect it over HDMI, but as soon as I attempt to switch to that input, I see the Shield interface for just one second, then the screen goes black and I see a spinning wheel for five seconds, then nothing but black. 

Whatever I do, I can't get the Shield display back on. If I reboot the Shield (by pulling the power and re-inserting it) - the same thing happens: I get the NVidia logo, but as soon as the interface is ready, it goes black, spinning wheel, black. 

I'm assuming there is some sort of "smart" function going wrong here, but I can't change anything on the Shield as I can't see it - do I change something on my Samsung TV?

[Toddy94]

Tv is faulty try in a different hdmi slot see what happens

[MungoBBQ]

Answering myself with the solution in case anybody else has similar problems: 

I was using an HDMI switch between the Shield and the TV and it seems that this switch is not compatible with the TV somehow. When I connect the Shield directly over HDMI to the TV,  everything works as it should.