I don't have permissions to execute the command

Hello I need help, I want my item to execute a command it executes but I get that I do not have permissions to execute that range help please

here the class

package nikbas.pelusa.items;

import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;
import net.minecraft.client.renderer.texture.IIconRegister;
import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.server.MinecraftServer;
import net.minecraft.world.World;
import nikbas.pelusa.NarutoMod;
import nikbas.pelusa.lib.Reference;

public class ItempelusaItem extends Item {

    public ItempelusaItem(){
        super();
        this.setFull3D();
        this.setUnlocalizedName("pelusaItem");
        this.setCreativeTab(NarutoMod.pelusaTab);
        this.setMaxStackSize(1);
        
        
    }
    @Override
    @SideOnly(Side.CLIENT)
    public void registerIcons(IIconRegister iconReg){
        itemIcon =  iconReg.registerIcon(Reference.MOD_ID + ":" + this.getUnlocalizedName().substring(this.getUnlocalizedName().indexOf(".")+1));
    }
    @Override

      public ItemStack onItemRightClick(ItemStack itemStack, World world, EntityPlayer sender)

      {

      //String var1 = "/summon LightningBolt ~1 ~1 ~1";

      String var1 = "/time set day";
      

      MinecraftServer.getServer().getCommandManager().executeCommand(sender, var1);

      return itemStack;
      }
}