Atem mini: Video does not show although camera is recognized

Hi there,
Anais from Germany here
I wonder if someone could give me a hint:
I have installed my Atem mini  together with a marshall cv 506 camera (connected via hdmi cable on port 1)  and using obs studio which is linked to youtube for livestreams.
Obs studio recognizes the marshall camea which I oviously chose as  video input device (?) and also records live streams but the video remains black, it is not visibly recorded. Yes, of course I removed the cover from the cameras lense and pressed the correct buttons on my Atem mini!...
Does anyone have an idea
Thank you very much 
Kind regards
Anais
 

Your camera appears to have a number of output resolutions the ATEM Mini won't recognise.

So first, ensure your camera output is set to one of the following ATEM-compliant resolutions:

1080p23.98, 1080p24, 1080p25, 1080p29.97, 1080p30, 1080p50, 1080p59.94, 1080p60.

1080i50, 1080i59.94, 1080i60.

720p50, 720p59.94, 720p60.

If you've set a compliant resolution and Input 1 still doesn't work, try inputs 2-4, as Input 1 differs slightly to Inputs 2-4 in respect to colour space (Input 1 is YUV only, inputs 2-4 are YUV & RGB).

Last, avoid using regular HDMI cable over 10 metres (the ATEM inputs can lose sync on long HDMI cables). If you do need a 10 metre-plus HDMI cable run, switch to a Fibre HDMI cable. They are readily available up to 150 metres off Amazon. Note: Fibre HDMI only works one-way, so ensure the connector marked Source is connected to the camera).

Hello, Louis
thank you very much for detailed reply.
My HDMI cable is only about 2 meters long and should therefore work properly I guess....I will therefore try to solve the problem by following your instructions above and possibly get back to you.
Best regards
Anais