Hi Shahrukh,
As per problem description and symptoms report, suspected issue with Power supply backplane, however you can follow below action to isolate the issue.
Action1:
Power DOWN the server, remove power cord and clear the NVRAM using system maintenance switch number 6. Once done, power ON the server and do the below setting in BIOS:
Select the Advanced menu.
Scroll down to IPMI and press the ENTER key.
Scroll down to the System Event Log and press the ENTER key.
At the Clear System Event Log selection, press the ENTER key to toggle between Enable and Disable. Select Enable.
Press the F10 key to save the changes and exit the BIOS Setup. Recycle the server once BIOS setting is done.
Action2:
Please confirm if server configured with a 500W High Efficiency Multi-Output Power Supply (Part Number 506077-001) and power supply white sticker reads Rev A or Rev B. If the power supply labelled with Rev A or Rev B then check by replace power supply using Spares Kit 506247-001.
Action3:
If none of these actions remedy the situation, then suspected issue with Power supply backplane.