User Error
A User Error is an error made by the human User of a complex system, usually a computer system. Also known as PEBMAC1, ID-10-T, PICNIC2, or IBM Error3. One should replace the User and try again.
There is no such thing as a User Error. There is nothing that a User should be able to do that would make the system behave unexpectedly. What it really means is that the system doesn’t have proper Exception Handling, or that the system was not designed well enough, only taking Happy Paths into account, for example.