[SOLVED] Help with PlayerPrefs.SetInt

I have a script which regenerates one life every 30 minute and then i can subtract one life by clicking a button that activates a "Subtractlife" function. The subtract function bit looks like this

 static var maxLives = 5;
 
 static var lives = 5;
 
 static var RegenInterval = 1800; // 30min * 60
  
 static var nextLife = 0;
 
 static function SubtractLife(){
     if(lives <= 0) 
         return false;  
     if (lives == maxLives)  

     {
         nextLife = UnixTimestamp() + RegenInterval;
     }
     PlayerPrefs.SetInt("nextLife", nextLife);
     lives--;
     PlayerPrefs.SetInt("lives", lives);
     return true;
 }

Now my problem is, that when i play my game in Unity, it works but when i play it on my phone it doesnt function properly. I think it is because i get this error "TrySetInt can only be called from the main thread. Constructors and field initializers will be executed from the loading thread when loading a scene. Don't use this function in the constructor or field initializers, instead move initialization code to the Awake or Start function." But when i do as the error says and put the PlayerPrefs.SetInt to the start function, the error stops showing but the script doesnt function properly in the game. Am i doing something wrong?