It is imperative to professionally communicate with customers while answering questions and explaining a series of steps while troubleshooting a problem. The key to answering this question is knowing that you want to tread lightly and not upset a user by pointing out the error is actually with them. Some easy ways to go about a scenario like this is to use phrases like 'a lot of our customers have this issue as well.' That way, the user can take comfort in knowing they aren't the only ones experiencing this issue.