Sophos XG Firewall reboted after hogh CPU consumption - Where to find logs

Hello everyone, 

We have a Sophos XG Firewall 310 with SFOS 18.0.4 MR-4 that after a high CPU comsumption became unavailable and rebooted.

I´d like to know what kind of logs or guide I can check to find out what processes (if any) caused that.

Any commands that can shed some light on this subject would be helpful

Thanks in advanced.