The interviewer is looking for insights into your significant client's pain points and how you overcome them. Your answer will speak to your emotional intelligence and indicate whether such setbacks affect your performance or client relations. If responded to correctly, this question also allows you to help the interviewer picture you in this role with Accenture. Walk the interviewer through your client's situation, and share with them how you overcame the hurdle with professionalism and poise. Showcase your strong communication skills, how you turned the situation around, and what you learned from the experience. Go the extra mile and detail how you've applied those lessons toward greater successes.