Repeated attempts to 'Reboot' talos-r4-snow-006 (aka AA5) on pdu1.r102-4.build.scl1 doesn't result in a network accessible slave. Please check inventory info for PDU is correct, or if another switch port died.
Usually this means that the machine has turned itself off as opposed to being hung (if the machine is off, it won't turn back on with a power cycle). Might want to check hardware diagnostics, since a machine turning itself off is somethings the sign of the logic board starting to go.
Talos-r4-snow-006 was indeed powered off. I've turned it on and was able to ping it.