I had been troubleshooting a DL380 server and replaced bad memory. I had the server powered off and connected to it using iLO. I used iLO to send power signal to the server so that I could watch it boot up. For some reason right after I powered on the server, I lost connectivity to iLO and the blue UID light on the server remained on.
Once Windows came up, I checked the HP System Management software, and it did not list an iLO management processor like the other servers did. I figured that iLO was hung, so I shutdown the server. Still no response from iLO, so I checked BIOS with a physical monitor and keyboard. Upon boot, it did not show the message to press a function key to configure iLO.
In order to reset iLO, I had to completely unplug both power supplies from the back of the server. After powering the system on again, I then saw the option to configure iLO. I saw that it had an IP address but I still could not connect. The blue UID light was off though. After the system came back up, I had to reset the iLO interface through the HP System Management software before it would work again correctly.