[08:38:21 INFO]: NickGFX issued server command: /blockstop
[08:38:21 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'blockstop' in plugin MiningLeaderboard v1.0_MC-1.8.8
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[spigot.jar:git-PaperSpigot-"4c7641d"]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:146) ~[spigot.jar:git-PaperSpigot-"4c7641d"]
        at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:666) ~[spigot.jar:git-PaperSpigot-"4c7641d"]
        at net.minecraft.server.v1_8_R3.PlayerConnection.handleCommand(PlayerConnection.java:1189) [spigot.jar:git-PaperSpigot-"4c7641d"]
        at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java:1001) [spigot.jar:git-PaperSpigot-"4c7641d"]
        at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:45) [spigot.jar:git-PaperSpigot-"4c7641d"]
        at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:1) [spigot.jar:git-PaperSpigot-"4c7641d"]
        at net.minecraft.server.v1_8_R3.PlayerConnectionUtils$1.run(SourceFile:13) [spigot.jar:git-PaperSpigot-"4c7641d"]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_171]
        at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_171]
        at net.minecraft.server.v1_8_R3.SystemUtils.a(SourceFile:44) [spigot.jar:git-PaperSpigot-"4c7641d"]
        at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:774) [spigot.jar:git-PaperSpigot-"4c7641d"]
        at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:378) [spigot.jar:git-PaperSpigot-"4c7641d"]
        at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:713) [spigot.jar:git-PaperSpigot-"4c7641d"]
        at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:616) [spigot.jar:git-PaperSpigot-"4c7641d"]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_171]
Caused by: java.lang.ClassCastException: org.bukkit.craftbukkit.v1_8_R3.CraftOfflinePlayer cannot be cast to org.bukkit.entity.Player
        at tk.sherrao.bukkit.miningleaderboard.Leaderboard.update(Leaderboard.java:54) ~[?:?]
        at tk.sherrao.bukkit.miningleaderboard.BlocksTopCommand.onExecute(BlocksTopCommand.java:22) ~[?:?]
        at tk.sherrao.bukkit.utils.command.SherCommand.onCommand(SherCommand.java:46) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[spigot.jar:git-PaperSpigot-"4c7641d"]
        ... 15 more