Focus on when you recognised the problem, what you did about it, and what you changed for future projects. Recovery is more impressive than perfection.
Best answers show: early recognition of problems (not waiting until disaster), transparent communication with stakeholders, root cause analysis, corrective actions taken, and lessons learned. Look for accountability rather than blame-shifting. The recovery plan matters more than the failure.
Every PM has had a project go wrong. The question is how they handled it. Red flag: never having a project fail (either very junior or not honest). Good sign: honest reflection and systemic changes made.