Autorank error | 1.15.1, PaperMC #57

[07:41:17 ERROR]: [Autorank] Could not hook into a dependency:
Cause:
[07:41:17 WARN]: java.lang.NoClassDefFoundError: me/lucko/luckperms/LuckPerms
[07:41:17 WARN]:        at me.armar.plugins.autorank.permissions.handlers.LuckPermsHandler.setupPermissionsHandler(LuckPermsHandler.java:166)
[07:41:17 WARN]:        at me.armar.plugins.autorank.permissions.PermissionsHandler.<init>(PermissionsHandler.java:20)
[07:41:17 WARN]:        at me.armar.plugins.autorank.permissions.handlers.LuckPermsHandler.<init>(LuckPermsHandler.java:22)
[07:41:17 WARN]:        at me.armar.plugins.autorank.permissions.PermissionsPluginManager.searchPermPlugin(PermissionsPluginManager.java:49)
[07:41:17 WARN]:        at me.armar.plugins.autorank.hooks.DependencyManager.loadDependencies(DependencyManager.java:150)
[07:41:17 WARN]:        at me.armar.plugins.autorank.Autorank$2.run(Autorank.java:326)
[07:41:17 WARN]:        at org.bukkit.craftbukkit.v1_15_R1.scheduler.CraftTask.run(CraftTask.java:84)
[07:41:17 WARN]:        at org.bukkit.craftbukkit.v1_15_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:452)
[07:41:17 WARN]:        at net.minecraft.server.v1_15_R1.MinecraftServer.b(MinecraftServer.java:1179)
[07:41:17 WARN]:        at net.minecraft.server.v1_15_R1.DedicatedServer.b(DedicatedServer.java:417)
[07:41:17 WARN]:        at net.minecraft.server.v1_15_R1.MinecraftServer.a(MinecraftServer.java:1106)
[07:41:17 WARN]:        at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:933)
[07:41:17 WARN]:        at java.lang.Thread.run(Unknown Source)
[07:41:17 WARN]: Caused by: java.lang.ClassNotFoundException: me.lucko.luckperms.LuckPerms
[07:41:17 WARN]:        at java.net.URLClassLoader.findClass(Unknown Source)
[07:41:17 WARN]:        at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:139)
[07:41:17 WARN]:        at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:85)
[07:41:17 WARN]:        at java.lang.ClassLoader.loadClass(Unknown Source)
[07:41:17 WARN]:        at java.lang.ClassLoader.loadClass(Unknown Source)
[07:41:17 WARN]:        ... 13 more
[07:41:17 WARN]: [Autorank] Task #104 for Autorank v4.3.1 generated an exception
java.lang.NullPointerException: null
        at me.armar.plugins.autorank.validations.ValidateHandler.validatePermGroups(ValidateHandler.java:42) ~[?:?]
        at me.armar.plugins.autorank.validations.ValidateHandler.startValidation(ValidateHandler.java:25) ~[?:?]
        at me.armar.plugins.autorank.Autorank$2.run(Autorank.java:341) ~[?:?]
        at org.bukkit.craftbukkit.v1_15_R1.scheduler.CraftTask.run(CraftTask.java:84) ~[patched_1.15.1.jar:git-Paper-57]
        at org.bukkit.craftbukkit.v1_15_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:452) ~[patched_1.15.1.jar:git-Paper-57]
        at net.minecraft.server.v1_15_R1.MinecraftServer.b(MinecraftServer.java:1179) ~[patched_1.15.1.jar:git-Paper-57]
        at net.minecraft.server.v1_15_R1.DedicatedServer.b(DedicatedServer.java:417) ~[patched_1.15.1.jar:git-Paper-57]
        at net.minecraft.server.v1_15_R1.MinecraftServer.a(MinecraftServer.java:1106) ~[patched_1.15.1.jar:git-Paper-57]
        at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:933) ~[patched_1.15.1.jar:git-Paper-57]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_231]