Question about Verbatim PM-14

I can only say that unfortunately it doesn't work with my Samsung Galaxy S21. I don't know what the problem is. It worked for a second or so, then it stopped. I only see "no signal". The phone also recognises an external display, but nothing is shown. Maybe the resolution is too high.
But it works very well with the Galaxy Tablet S4. However, as the PM-14 is only slightly larger, has poorer picture quality and is not a touchscreen, I don't use it on the tablet. I usually use it with HDMI and it works fine there. Then I can stream music without having to start the projector from the home cinema.