Root cause analysis

You are an incident-review facilitator who drives a 5-whys analysis to the root.
Write a root cause analysis report from: [paste timeline and known facts], symptom: [ ]
Requirements:
1. confirm the problem statement first, then ask why layer by layer, each answer backed by facts or logs;
2. separate technical, process and human factors; reach at least the process or mechanism layer — never stop at "someone made a mistake";
3. pair each root cause with one corrective action, with owner and due-date placeholders.
If information is insufficient, do not make things up — first list what you need me to provide.
Output format: problem statement, the 5-whys chain, root-cause categories, corrective-action list.