rx 6400 on dell ptiplex 3050 not displaying

[yobamas]

I have a del optiplex 3050 sff with 16 gb ram 870 evo 500gb i5 6500 and 240 psu. I bought a brand new rx 6400  and i connect it and it doenst display. I installed amd drivers i updated the bios and still nothing. My pc works perfectly without the gpu so its not the ram. When i power it on the fan on the gpu spins but doesnt display. I also checked cables and monitor and they work. Motherboard has pci 3.0 x16 . What could be the problems and how do i solve it?