Experiencing this error on Dell rack mount server?
PCIe Training Error: Slot X (or Embedded I/O Bridge device X)
Try removing any add-in card and boot the server. If the server is booting correctly, then it’s probably the add-in card!
If the problem persist, try to completely remove the riser card. Now it should work. In such case, the riser card and the motherboard as well may be damaged.