help what is persistent level and why is it giving me errors

LogBlueprint: Error: [Compiler PersistentLevel.lvl] Spawn node Create Widget must have a class specified. from Source: /Game/buildings/Maps/lvl.lvl:PersistentLevel.lvl

what is persistent level.lvl i never created this file i dont have it in my directory i cant locate it why is it giving me errors

Are you creating a widget in the level blueprint?

yes turns out the problem was that the widget i was creating had a button that would send you to another level and that another level had a widget that wasnt set