Intel NUC HDMI output to ATEM connection issue

I intend to use my Intel NUC8i5BEK with integrated Iris Pro 655 graphics as a compact media player with HDMI output connected to ATEM switcher. The installed OS is Windows 10 Pro 1803. When I connect the HDMI cable between NUC and one of ATEM's input nothing happens in the Display Settings. No second display appears, so I can't even select a resolution for ATEM.

I never faced this issue before with other my computers (MacPro with NVidia, Desktop with i4770 CPU and Intel HD 4600 graphics) - all them works fine but NUC.

Usual monitor or TV set connected to NUC's HDMI output is recognized as second display and I can set output resolution to 1080i50 so HDMI output is OK.

Why NUC does not recognize ATEM? Anybody faced this?

Probably the EDID table of the Atem is not correctly ingested by the integrated video device in the NUC.

And if they do not play well together then your videocard might not go for it.

Search around how to Force that videocard to output. Or maybe a cheap HDMI splitter in between may do the trick.

After some investigation I noticed that issue is related to older version of ATEM (I tried 1ME and Production Studio 2K). With Production Studio 4K everything is OK !
And yes, HDMI splitter helps to fix the problem.

in that case we use a EDID dongle like this (should be in every technicians pocket )
the dongle is programmed with the usual needed resolutions.

https://www.lindy.de/HDMI-EDID-Emulator.htm?websale8=ld0101&pi=32103