This is part of Factions, it's a new feature, you must wait a while before you can use your kit again. Hope I helped you out!
Bruh, it says not improperly defined, I been playing factions for 8 years I know how kits work, i waited 48 hours
Ah, sorry. Didn't see that part. Maybe you can report this bug in the (Reports) section. EDIT: I tried using my kit myself and I got the same result you did so your not alone with this issue.