org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[custom.jar:git-PaperSpigot-ea452ce]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[custom.jar:git-PaperSpigot-ea452ce]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:509) [custom.jar:git-PaperSpigot-ea452ce]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:494) [custom.jar:git-PaperSpigot-ea452ce]
        at org.bukkit.craftbukkit.v1_7_R4.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:242) [custom.jar:git-PaperSpigot-ea452ce]
        at org.bukkit.craftbukkit.v1_7_R4.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:212) [custom.jar:git-PaperSpigot-ea452ce]
        at net.minecraft.server.v1_7_R4.PlayerConnection.a(PlayerConnection.java:681) [custom.jar:git-PaperSpigot-ea452ce]
        at net.minecraft.server.v1_7_R4.PacketPlayInBlockPlace.a(PacketPlayInBlockPlace.java:50) [custom.jar:git-PaperSpigot-ea452ce]
        at net.minecraft.server.v1_7_R4.PacketPlayInBlockPlace.handle(PacketPlayInBlockPlace.java:86) [custom.jar:git-PaperSpigot-ea452ce]
        at net.minecraft.server.v1_7_R4.NetworkManager.a(NetworkManager.java:190) [custom.jar:git-PaperSpigot-ea452ce]
        at net.minecraft.server.v1_7_R4.ServerConnection.c(ServerConnection.java:81) [custom.jar:git-PaperSpigot-ea452ce]
        at net.minecraft.server.v1_7_R4.MinecraftServer.v(MinecraftServer.java:799) [custom.jar:git-PaperSpigot-ea452ce]
        at net.minecraft.server.v1_7_R4.DedicatedServer.v(DedicatedServer.java:307) [custom.jar:git-PaperSpigot-ea452ce]
        at net.minecraft.server.v1_7_R4.MinecraftServer.u(MinecraftServer.java:646) [custom.jar:git-PaperSpigot-ea452ce]
        at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:551) [custom.jar:git-PaperSpigot-ea452ce]
        at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:628) [custom.jar:git-PaperSpigot-ea452ce]
Caused by: java.lang.ClassCastException: org.bukkit.craftbukkit.v1_7_R4.CraftOfflinePlayer cannot be cast to org.bukkit.entity.Player
        at zuhc.staffmode.OnlineStaff.openOnlineGUI(OnlineStaff.java:41) ~[?:?]
        at zuhc.staffmode.OnlineStaff.onPlayerInteractEvent(OnlineStaff.java:63) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_211]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_211]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_211]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:298) ~[custom.jar:git-PaperSpigot-ea452ce]
        ... 15 more