Your question is Debugging With Limited Visibility. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
How do you handle debugging a system failure in a production environment where you have limited visibility? Explain how you would establish the scope of impact, gather reliable signals, protect customers, and coordinate the response. Address how you would decide between mitigation, rollback, escalation, and deeper investigation while preserving an evidence trail.