diff --git a/src/main/java/io/github/znetworkw/znpcservers/commands/CommandInvoker.java b/src/main/java/io/github/znetworkw/znpcservers/commands/CommandInvoker.java
index 53cdab7..b7545f4 100644
--- a/src/main/java/io/github/znetworkw/znpcservers/commands/CommandInvoker.java
+++ b/src/main/java/io/github/znetworkw/znpcservers/commands/CommandInvoker.java
@@ -4,9 +4,7 @@ import java.lang.reflect.Method;
 
 public class CommandInvoker {
     private final Command command;
-
     private final Method commandMethod;
-
     private final String permission;
 
     public CommandInvoker(Command command, Method commandMethod, String permission) {
@@ -16,8 +14,12 @@ public class CommandInvoker {
     }
 
     public void execute(CommandSender sender, Object command) throws CommandPermissionException, CommandExecuteException {
-        if (this.permission.length() > 0 && !sender.getCommandSender().hasPermission(this.permission))
+        if (!(sender instanceof Player) && this.permission.length() == 0) {
+            throw new CommandPermissionException("Only players may execute this command.");
+        }
+        if (this.permission.length() > 0 && !sender.getCommandSender().hasPermission(this.permission)) {
             throw new CommandPermissionException("Insufficient permission.");
+        }
         try {
             this.commandMethod.invoke(this.command, sender, command);
         } catch (IllegalAccessException | java.lang.reflect.InvocationTargetException e) {