The yellow light on the front panel of the server is indicative of a potential hardware failure due to a faulty part or unsecure connection.
When you remove the cover of the server system, you see that the corresponding yellow/amber light is next to a dual in-line memory module (DIMM).
To validate if this issue is due to a bad connection, faulty RAM, or failed memory port, you need to power down the system and swap places for the memory modules. Upon moving the modules and powering on the server, if the warning light does not return, the issue is possibly due to an unsecure connection of the DIMM on the motherboard of the server.
If the issue still persists, then the problem could be because of a faulty DIMM. Contact the reseller or open a Service Request using the Service Request Tool.