What is the cause of the bug?

 using UnityEngine;
 using System.Collections;
 
 public class SomeCode : MonoBehaviour{
 void OnGUI()
     {
         variable = GUI.TextField(new Rect(210, 110, 160, 30), variable);
         if (GUI.Button(new Rect(40, 430, 160, 30), "Show a message"))
         {
             if (variable != "")
             {
 
                 GUI.Label(new Rect(210, 430, 100, 100), "This DOES NOT Work!");
 
                 Debug.Log("This works as well");
             }
             else
             {
                 //Write an error
             }
         }
     }
 }
 

I tested this code in Microsoft visual studio with unity plugin and it gave no errors.