On some servers if you have a kit for something on it you can only have kits every certain amount of time eg. Yearly kits, monthly kits or daily kits so if you have used it you might not be able to use it again for a certain amount of time or if you havent used the kits at all then you could have had a ranking on the server but that finished so you cant access these kits anymore or its some kind of bug and you should tell the server owners or mods