The server stopped turning on how to find the problem?

Question

Supermicro

Good afternoon, yesterday there was a failure at about 6 am, and the server on supermicro x9qri-f + stopped starting with 4 processors, with 1-2-3 norms, as I insert 4 cyclic reboot. In the logs that at 6 in the morning there was a lack of power, etc., the log does not write anything else, bios is the last one, threw off the shaman from the oz, the problem was with the power supply of the outlet, it was eliminated. Who has any suggestions?