DeckLink Quad HDMI Recorder does not support 60 Hz

Hello,
I'm Marvin and I'm helping a friend with IT at his event technology company.
We have a problem with the DeckLink Quad HDMI recorder. We have a PC that is about two years old with this card and a new PC with this card. On both we get no input signal when the output is set to a resolution of 1080p and a frame rate of 60 Hz. 25 Hz works, 50 Hz works, 59.94 Hz works. According to the data sheet, the card should also be capable of 60 Hz. Do you have any idea why this might be?
Thank you very much.

I’m not seeing RGB support for 1920x1080 instead 1920x1200. 60hz is more commonly RGB than YCrCb. Maybe make sure the graphics card is outputting YCrCb when switched to 60hz?

Good Luck