I run ROCK on a NUC headless so I would like to know how is the symptom of a crashed ROCK.
Assuming your network connection is OK, then a message on a Remote that you are not connected to Core or the inability to connect to Core when prompted.
Also, not being able to connect to the Web GUI.
OK not being able to access Web GUI is the key here.
Check for uptime on ROCK webpage. This corresponds to a reboot I had to do because of a networking issue (not Roon related) 32 days ago and the last Software upgrade.
For avoidance of doubt, does a Roon crash caused by running out of RAM cause Roon OS to restart or just Roon Server?