When you are interviewing for a job, no matter what type of job it happens to be, you can usually rely on the fact that the employer will be interested in finding out what you have accomplished in prior jobs as well as what you were not able to accomplish. This is a fairly common question and one that you should be prepared to answer because there is a good chance that it will be presented to you.
Everyone has failed at something from time to time. The only difference is the severity of the failure or at least how severe you perceive the failure to be. Consequently, if you are asked this question you should not have any problems coming up with a relevant example to share, but you do need to take care regarding what you share and what you do not.
The best way to respond to this type of question is to provide an example of a situation that is relatively minor but is one which you will be able to transfer into a positive. For example, you might say that at one point you were working in a particular job and were faced with a tight deadline. In that situation you found that you needed to adjust the workload in order to get everything back on track and complete the project on time and actually ahead of schedule. This clearly shows that you take important matters such as deadlines seriously and also that you are able to take a negative and turn it into a positive.
When answering this question you should make sure that you never respond by describing any type of situation which you would consider to be a big failure. You certainly do not want to venture into any territory where you talk about being terminated from a position even if that is what actually happened. Unless you are directly asked about something like this by the interviewer, it is better to just leave such topics alone and not introduce them into the interview. Choosing a situation that is relatively minor and then showing you were able to turn it into a positive shows your dedication to the job and also demonstrates that you are able to take even bad situations and make something good out of them.