I know what I'm going to ask is a pretty general question, but it's my first Linux installation and I don't know how to start looking where the problem is.
I have a RaspberryPi 4 / 8GB ram with Ubuntu Server installed. I'm running a couple of service that I need to maintain an airplane radar I have at home. It worked smoothly for 2 months, then it started having this problem: after 24-36 hour from restarting the RPi becomes unreachable (ping, SSH, HTTP server) and the only way to fix is unplug and plug again power connector.
I have any idea of what could be the problem, but I also don't know how to look for the cause. Is there any system log that I can read after restarting that could tell me what happened?
Here is the log: https://pastebin.com/tHNDM80e.
I see that a problem happend with the memory at around 13.50, but the Rasp went offline one hour later. Are these problems correlated? DO you know how can i solve?