Cant access server

I recently installed a RAM on the server(T420) everything runs smoothly then after 4 days I wasn't able to Remote the server, tried to connect a monitor a " No Signal " popup on the monitor tried different monitor and VGA cable still no display, tried to plug in a usb keyboard and mouse but in doesn't power up. But the server is still up and running, I can still access the shared folder thru network, I can still access iDrac via browser. Should I do a cold reboot ?

Hello,

How are you trying to access the server? Is this an iDRAC virtual console error, or an RDS connection that is erring?

A reboot may help, but if it comes to that, I would recommend a power drain. You would be able to do that by just unplugging the server and holding the power button down for 30 seconds. You can then bring it back up as normal. You might also try resetting the iDRAC from the web GUI, since it is available, if it is the virtual console that is failing.

Before I was accessing the server via RDP and connecting monitor and mouse/keyboard, and license is not in enterprise. I also reset the iDrac still the same, all hardware are healthy based on iDrac

I cant reboot the server because it is hard to tell if the server will come back up.