No picture on projector when I play videos from my pc?

If I connect my projector to my laptop via hdmi and go to various streaming platforms (e.g. HD films or burning series) then a black area is simply displayed where the video should be.

It's easy on youtube and also with my wireless hdmi stick. (but wants it with cable)

Can that be because I bought a new laptop and the projector is a bit older and therefore does not support HDCP?

If not, what can I do about it?

You can only do something against HDCP-protected content by transmitting an analog signal to the projector - with VGA, so to speak…

because HDCP is a copy protection that can't be removed… With Apple laptops it is very bad…