Macbook Pro 16" USB-C to DisplayPort not working I'm trying to connect a MacBook Pro 16&quot; to my external display through DisplayPort with these devices :

Cable Matters Adaptater USB C to DisplayPort
DisplayPort Cable
External display : iiyama prolite b2783QSU

But it's not working.
When I plug it in, the external display goes out of sleeping mode, but the MBP does not detect it and after a couple of seconds, the display displays a &quot;no input detected&quot; message and goes back to sleep.
I've tried :

Reseting the SMC and NVRAM and tried all 4 usb slots.
Switching off and unplugged the display, plugged it back in etc.
Restarting in clamshell
Force detect the display (the display goes out of sleeping mode, but then wont be detected)

I've tested the cable, adapter and screen with another computer and everything works fine.
Is there something I'm missing here ?
Is it possible that my external display isn't compatible ?
== Edit ==
It looks like incompatibility between MacOS and this iiyama model (or I guess this DisplayPort version).
It also seems to be a software problem, since it works under Windows/Bootcamp (!)
I've raised the issue to the Apple support, but of course no answer, and I think no hope of this getting solved.
Basically, I need to buy a new screen... sad.
You just need a simple Type C DisplayPort cable.
The confusion comes from how “USB-C” was implemented.  USB-C is just the physical port type.  The ports on your MacBook Pro are actually Thunderbolt 3 ports and they use a Type C connector.  Thunderbolt has several signals:  PCIe, USB 3.x, DisplayPort and Power.
So, that port is natively outputting DisplayPort and the adapter you purchased is an actual video adapter that connects to USB and outputs DisplayPort.  It’s not working because your Mac doesn’t have the drivers for that particular adapter.