Firewall often reboots on its own

The firewall does reboot on its own but we also see some irregularities without reboots. The one impacting the most is that on one of our IPSec VPN, we have 5 phase 2 that are randomly dropping multiple times in a day (have to bring UP manually, phase 1 stays up). At the same time, we can see that the configuration interface is going down for a few seconds (connection interrupted in the web browser, on a local LAN, and not going through said VPN).

 and we have also DHCP problems and that we wanted to diagnose, the firewall has restarted