Why does Hass OS stop working after 2 weeks?

i have HassOS running in Proxmox after following this YT guide. strangely Hass stops working almost after 14 days while Proxmox still works fine. so i know it’s not the desktop hardware itself. when Hass hangs, i have to log into Proxmox and restart the Hass OS, not Proxmox. any idea how to find out why Hass failed?
for now, i will try to use this service to restart HA weekly
service: homeassistant.restart