The billing service restarts by itself every twenty minutes

Groupe Sefrioui Logistique issues its customer invoices with a Java (Spring Boot) application hosted on a Rocky Linux 9 virtual machine (8 GB of RAM) in its Sidi Maârouf datacenter. Two services run on this VM: facturation (the main application) and rapports (nightly PDF generation).

Since Friday evening, facturation has been “restarting by itself”: the accountants lose their input several times an hour. It is month-end closing, and the finance department calls every ten minutes. The development team insists: “no exception in our logs, it's not the application”.

You are a level 2 Linux administrator. Find the root cause and stabilise the service.