Code:
[13:02:25] [Server thread/ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'mm' in plugin MythicMobs v2.5.0
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot-1.10.2.jar:git-Spigot-570526c-c1b529e]
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[spigot-1.10.2.jar:git-Spigot-570526c-c1b529e]
at org.bukkit.craftbukkit.v1_10_R1.CraftServer.dispatchCommand(CraftServer.java:647)...