To understand Known Error Database or KEDB anyone should know that there are three ITIL terms that you should be familiar with such as incident, problem and known error. What could be tagged as incident? Simple, if your email service goes down without notice from your provider, could be tagged as an incident. In this example, the reason behind the email outage is the problem, so a problem is the underlying cause of an incident. In other words, this is the thing that caused the issue in the first place.