8 Port HDMI Splitter no video Mac/Dell

Greetings,

I have the StarTech 8 port HDMI Splitter on a M4 pro Macbook pro. When hooked up to 1 -4 Dell Monitors the screens do not display any picture. If i hook up Samsung TVs, they immediately display. We tried various resolutions and refresh rates but none work. Any guidance is greatly appreciated.