Kashikomari, I would start with making sure the server is up to date. Normally issues like this are due to it being very behind in updates, but you may also want to clear the hardware logs as well. Let me know if this helps.  
Hi CommunityMy old but reliable PowerEdge works fine but for a few days ago:Turn system power on... the system status indicator (blue) is on & caution (amber) is off, Ok.Between begin postscreen and Windows start... the system status indicator is off & caution is blinking, Why?When starting Windows... the system status indicator changes to on & caution to off, Ok.- No faults displayed on power supplies & discs LED's- All (visible) LED's inside are on green & constant- No error messages during post- Diagnostic does not report any problemsI'm a bit baffled...Does anybody know something about this behaviour?Cheers Jürg
Strange error status Dell PowerEdge 2600