ASR detected by system ROM

Hello, colleagues!

I have a server HP ProLiant ML350p Gen8 with Windows Server 2008 R2 Enterprise on board.

Yesterday server was rebooted without my permission.

At iLO log I found one event at time, when server was rebooted:

Event ID: 46

Class: Automatic Server Recovery

Description: ASR Detected by System ROM

At Event log in Windows Server I also found one critical error:

Log Name: System
Source: Microsoft-Windows-Kernel-Power
Event ID: 41
Level: Critical
Description:
The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.

EventData
BugcheckCode 0
BugcheckParameter1 0x0
BugcheckParameter2 0x0
BugcheckParameter3 0x0
BugcheckParameter4 0x0
SleepInProgress false
PowerButtonTimestamp 0

I have no memory dump for analize (it wasn't created) and have no another event at Windows event log.

Also, I have no idea, what could be the problem.

Tell me, please, direction to continue troubleshooting!