If you want a very overarching error, like to tell your boss why you need to fix the machine and not go into specifics of what is broken, I would classify it as a "feed error", as the spool and path to the extruder are part of what is conventionally the feeding system of the machine. However, that is a really nondescript word, as it also includes things like running out of filament, filament snapping on the path, being blocked at some point and getting ground away, a blob on the filament preventing it from being pulled in and many other errors that result in a failure to feed new filament into the extruder.
As 0scar pointed out, "filament entanglement on spool" would be the most specific description, but could be shortened to "tangled spool" as a sub-class of a feed error. Most people will understand what you mean by that. If that sounds too casual, "miswound spool" could stand as a substitute, though it is unclear if that is for not neatly wound or layer-interwound which results in the tangle. Maybe "Entwined filament" or "knotted filament" also might work as substitutes.