How to troubleshoot crash?

Running 3.14 ubuntu with asterisk image latest from but support seems to be going away. Have added some simple scripts to talking to an Arduino board but think the problem is more basic. Latest image ran ok for about a month but now is crashing almost daily. This is headless and when it crashes I can’t access it although it may still be running - I’m not sure… Hardly any experience looking at logs, etc. How do I figure out what is going on and how to fix - i.e. where to start?

If the fix is too involved I may just abandon asterisk for now and go with a maintained version of ubuntu (which one?) if that’s what’s needed for a stable system. The other scripts are more important now and I could run asterisk on a real PC box.