Making mistakes is human. It is how we deal with our mistakes, which is the true mark of one's character. The interviewer wants to know if you take actionable steps to remedy your mistakes before bringing them to the attention of our superiors, and if you take responsibility for your own actions. Lastly, the most important aspect of this question is whether you take your setbacks in stride, and turn failures into success by distilling the situation into a life lessons that you apply to your successes moving forward. By not repeating your mistakes, you shore yourself up for repeatable success. Give an example that demonstrates how you took responsibility for your error and fixed it. Also, what you learned from the experience as a result.