sensible toolbox error

[14:20:22] [Server thread/ERROR]: Error occurred while enabling SensibleToolbox vDEV - 45 (git dbcee02b) (Is it up to date?)
java.lang.NoClassDefFoundError: me/mrCookieSlime/Slimefun/Objects/SlimefunItem/SlimefunItem
	at io.github.thebusybiscuit.sensibletoolbox.SensibleToolboxPlugin.onEnable(SensibleToolboxPlugin.java:263) ~[?:?]
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:263) ~[patched_1.16.5.jar:git-Paper-788]
	at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:370) ~[patched_1.16.5.jar:git-Paper-788]
	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:500) ~[patched_1.16.5.jar:git-Paper-788]
	at org.bukkit.craftbukkit.v1_16_R3.CraftServer.enablePlugin(CraftServer.java:518) ~[patched_1.16.5.jar:git-Paper-788]
	at org.bukkit.craftbukkit.v1_16_R3.CraftServer.enablePlugins(CraftServer.java:432) ~[patched_1.16.5.jar:git-Paper-788]
	at net.minecraft.server.v1_16_R3.MinecraftServer.loadWorld(MinecraftServer.java:594) ~[patched_1.16.5.jar:git-Paper-788]
	at net.minecraft.server.v1_16_R3.DedicatedServer.init(DedicatedServer.java:298) ~[patched_1.16.5.jar:git-Paper-788]
	at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:1069) ~[patched_1.16.5.jar:git-Paper-788]
	at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$a$0(MinecraftServer.java:291) ~[patched_1.16.5.jar:git-Paper-788]
	at java.lang.Thread.run(Thread.java:831) [?:?]
Caused by: java.lang.ClassNotFoundException: me.mrCookieSlime.Slimefun.Objects.SlimefunItem.SlimefunItem
	at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:155) ~[patched_1.16.5.jar:git-Paper-788]
	at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:114) ~[patched_1.16.5.jar:git-Paper-788]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:519) ~[?:?]
	... 11 more
[14:20:22] [Server thread/INFO]: [SensibleToolbox] Disabling SensibleToolbox vDEV - 45 (git dbcee02b)