With this question, the interviewer is assessing your ability to lead and influence. As with any other issue that arises in a project, you are expected to conduct a root-cause analysis. First, an effective answer will demonstrate that you are open to feedback from the team. Second, it will show the interviewer that you can analyze the feedback and get to the root of the issue. Lastly, you will want to emphasize that you can be responsible for motivating your team by providing specific examples of actions that will boost their morale.