Command Exception Error, why?

Hi! I get a Command Exception error when I perform certain commands. I can send code if needed.

This is the console error I get:

Code:

18.10 12:42:25 [Server] ERROR null
18.10 12:42:25 [Server] INFO org.bukkit.command.CommandException: Cannot execute command 'vanish' in plugin Nick-Vanish-GoldenGG v0.1 - plugin is disabled.
18.10 12:42:25 [Server] INFO at org.bukkit.command.PluginCommand.execute(PluginCommand.java:36) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:152) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at org.bukkit.craftbukkit.v1_12_R1.CraftServer.dispatchCommand(CraftServer.java:685) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at net.minecraft.server.v1_12_R1.PlayerConnection.handleCommand(PlayerConnection.java:1492) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at net.minecraft.server.v1_12_R1.PlayerConnection.a(PlayerConnection.java:1297) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at net.minecraft.server.v1_12_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at net.minecraft.server.v1_12_R1.PacketPlayInChat.a(PacketPlayInChat.java:5) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at net.minecraft.server.v1_12_R1.PlayerConnectionUtils.lambda$ensureMainThread$0(PlayerConnectionUtils.java:14) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_265]
18.10 12:42:25 [Server] INFO at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_265]
18.10 12:42:25 [Server] INFO at net.minecraft.server.v1_12_R1.SystemUtils.a(SourceFile:46) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:850) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:423) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:774) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:666) ~[patched_1.12.2.jar:git-Paper-1618]
18.10 12:42:25 [Server] INFO at java.lang.Thread.run(Thread.java:748) [?:1.8.0_265]

 

Start your server and watch the log, it'll likely tell you why.