Resolution is not saving.

I am having a problem with the resolution. The resolution is not saved. When I close the game and reopen it at first it opens fine and suddenly it changes to a default resolution and I have to change it again. I do not understand what is wrong in the code that the resolution is not saved. I already tried a thousand ways and I can't solve it. Here is the code that I am using to change the resolution and save it:

 public class LogicResolution : MonoBehaviour
 {
     public TMP_Dropdown resolutionsDropDown;
     public int optionIndex;
  
     void Start()
     {
         optionIndex = PlayerPrefs.GetInt("resolutionNumber", 2);
         resolutionsDropDown.value = optionIndex;
         AdjustResolution();    
     }
  
     public void AdjustResolution()
     {          
         if (resolutionsDropDown.value == 0)
             Screen.SetResolution(640, 360, Screen.fullScreen);
         else if (resolutionsDropDown.value == 1)
             Screen.SetResolution(1280, 720, Screen.fullScreen);
         else if (resolutionsDropDown.value == 2)
             Screen.SetResolution(1920, 1080, Screen.fullScreen);
         else if (resolutionsDropDown.value == 3)
             Screen.SetResolution(3840, 2160, Screen.fullScreen);
  
         PlayerPrefs.SetInt("resolutionNumber", resolutionsDropDown.value);
         optionIndex = resolutionsDropDown.value;    
     }

The default value is 1280x720 when I actually set it to start with 1920x1080.