Your question is Professional Disappointment. 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).
Biggest professional disappointment.
Asked in the Round 5 - Hiring Manager stage. Use a specific professional setback rather than a minor inconvenience or a hypothetical situation. Explain what happened, your role in the outcome, how you responded, and what changed in your approach afterward.
The interviewer is probing for ownership, emotional maturity, judgment, and the ability to learn without blaming others. A strong answer identifies the stakes, acknowledges your contribution to the disappointment, describes concrete corrective action, and ends with a measurable result or lasting change in behavior. Keep the focus on growth rather than defending the original decision.