I’m not a hardware expert but I’ll give it a shot. The card you got is probably PCI Express 16x. Some 8x slots will accept 16x cards but not all. PCI Express video cards are either 1x or 16x. You probably need a PCI Express 1x card. I’d pick a brand you like and get the cheapest model. PCI is another option. Graphics performance will be worse but it’s a server so does it matter?