Plugin not working "an internal error occurred while attempting to perform this command"

[AloneGamer]

The console says 

[17:58:39 ERROR]: null

org.bukkit.command.CommandException: Cannot execute command 'sw' in plugin SkyWars v1.4.0 - plugin is disabled.

	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:37) ~[patched_1.16.5.jar:git-Paper-771]

	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:159) ~[patched_1.16.5.jar:git-Paper-771]

	at org.bukkit.craftbukkit.v1_16_R3.CraftServer.dispatchCommand(CraftServer.java:826) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.PlayerConnection.handleCommand(PlayerConnection.java:2185) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.PlayerConnection.c(PlayerConnection.java:2000) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.PlayerConnection.a(PlayerConnection.java:1953) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.PacketPlayInChat.a(PacketPlayInChat.java:50) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.PacketPlayInChat.a(PacketPlayInChat.java:8) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.PlayerConnectionUtils.lambda$ensureMainThread$1(PlayerConnectionUtils.java:35) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.TickTask.run(SourceFile:18) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeTask(IAsyncTaskHandler.java:136) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.IAsyncTaskHandlerReentrant.executeTask(SourceFile:23) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeNext(IAsyncTaskHandler.java:109) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.MinecraftServer.bb(MinecraftServer.java:1266) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.MinecraftServer.executeNext(MinecraftServer.java:1259) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.awaitTasks(IAsyncTaskHandler.java:119) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.MinecraftServer.sleepForTick(MinecraftServer.java:1220) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:1134) ~[patched_1.16.5.jar:git-Paper-771]

	at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$a$0(MinecraftServer.java:291) ~[patched_1.16.5.jar:git-Paper-771]

	at java.lang.Thread.run(Thread.java:829) [?:?]

[_Tarna_]

Looks like the plugin may be outdated for the version your server is on or something else went wrong when it tried to enable.