1
HP Proliant DL380p Gen8 Boot loop
(alien.top)
Could be everything, but it has nothing to do with the OS ... I would try a minimal config (1 CPU, 1 memory, 1 PSU, no PCI cards, no disks / Disk Backplane).
I agree with ar0na, sounds like you got a hardware problem if you're not getting past POST. Depending on how comfortable you are with hardware (you should be if you're F'ing around with homelabbing), then I would follow his advice and start with the bare min to get started and keep adding one thing at a time to find the problem.
Sometimes....this kinda crap popping up is the best way to learn.
Good luck!