Question Why doesn't my RX 560 work ?

Aug 30, 2021
Hello! Today I bought a RX 560 GPU but when I put it into the MoBo and turn the system on it does not broadcast video.
I did not buy it new but used through Facebook Market.

My hardware is:
MoBo: Asus B-450m ii
Ryzen 5 1600 (6 cores, 12 threads)
GPU: RX 560
32 gb ram (2X16) at 2600 mhz.
750 Watt PSU.
1 tb hard disk.
Operating system: Ubuntu 20.04.

I'm using the displayport port of the gpu, I use an adapter to vga (it worked with my old gpu)

The weird thing is that the fans turn on but a few seconds later they stop and after another few seconds they turn on again.
My previous GPU is a Quadro fx-5800 4 gb.

If someone knows what is the problem I'd be very thankful.