Object to JSON Conversion

I want to convert the object into JSON string but when I try to convert using JSON utility it returns the empty string. Below is the code

         using UnityEngine;
         using System;
     
         public sealed class Player : MonoBehaviour
         {
             #region VARIABLES
             //Public Variables
             public static Player Instance { get; private set; }
     
             internal BibleVersions bibleVersion = BibleVersions.Web;
             internal Gender gender = Gender.Female;
             internal int experience = 0, requiredExperience = 0, level = 1, gold = 100, lastBonusTime = 0, lastEmptyBonusTime = 0, totalSavedCards = 1, totalSavedVerses = 1;
             internal int bookTextureIndex = 0, shieldTextureIndex = 0, hairTextureIndex = 0, topTextureIndex = 0, bottomTextureIndex = 0, bootTextureIndex = 0, gloveTextureIndex = 0, helmetTextureIndex = 0, skinIndex = 0;
             internal string bookID = string.Empty, shieldID = string.Empty, hairID = string.Empty, topID = string.Empty, bottomID = string.Empty, bootID = string.Empty, gloveID = string.Empty, helmetID = String.Empty;
             internal string joinedDate = string.Empty, lastActiveDate = string.Empty, premiumDate = String.Empty;
             internal bool ghostBan = false, disableUser = false;
             internal float averageDPS = 3.0f, huntDPS = 0.0f;
             #endregion
     
             void Awake()
             {
                 if (Instance != null)
                 {
                     DestroyImmediate(gameObject);
                     return;
                 }
     
                 Instance = this;
                 DontDestroyOnLoad(gameObject);
             }
     
             // Use this for initialization
             void Start()
             {
     Debug.Log(Str());
             }
     
             // Update is called once per frame
             void Update()
             {
     
             }
     
             public string Str()
             {
                 Player player1 = new Player();
                 player1.bibleVersion = SaveGameData.Instance.bibleVersion;
                 player1.experience = SaveGameData.Instance.experience;
                 player1.level = SaveGameData.Instance.level;
                 player1.gold = SaveGameData.Instance.gold;
                 player1.lastBonusTime = SaveGameData.Instance.lastBonusTime;
                 player1.lastEmptyBonusTime = SaveGameData.Instance.lastEmptyBonusTime;
                 player1.totalSavedCards = SaveGameData.Instance.totalSavedCards;
                 player1.totalSavedVerses = SaveGameData.Instance.totalSavedVerses;
                 player1.bookTextureIndex = SaveGameData.Instance.bookTextureIndex;
                 player1.shieldTextureIndex = SaveGameData.Instance.shieldTextureIndex;
                 player1.hairTextureIndex = SaveGameData.Instance.hairTextureIndex;
                 player1.topTextureIndex = SaveGameData.Instance.topTextureIndex;
                 player1.bottomTextureIndex = SaveGameData.Instance.bottomTextureIndex;
                 player1.bootTextureIndex = SaveGameData.Instance.bootTextureIndex;
                 player1.gloveTextureIndex = SaveGameData.Instance.gloveTextureIndex;
                 player1.bookID = SaveGameData.Instance.bookID;
                 player1.shieldID = SaveGameData.Instance.shieldID;
                 player1.hairID = SaveGameData.Instance.hairID;
                 player1.topID = SaveGameData.Instance.topID;
                 player1.bottomID = SaveGameData.Instance.bottomID;
                 player1.bootID = SaveGameData.Instance.bootID;
                 player1.gloveID = SaveGameData.Instance.gloveID;
                 player1.joinedDate = SaveGameData.Instance.joinedDate;
                 player1.lastActiveDate = SaveGameData.Instance.lastActiveDate;
                 player1.requiredExperience = SaveGameData.Instance.requiredExperience;
                 player1.premiumDate = SaveGameData.Instance.premiumDate;
                 player1.ghostBan = SaveGameData.Instance.ghostBan;
                 player1.disableUser = SaveGameData.Instance.disableUser;
                 player1.helmetID = SaveGameData.Instance.helmetID;
                 player1.helmetTextureIndex = SaveGameData.Instance.helmetTextureIndex;
                 player1.skinIndex = SaveGameData.Instance.skinIndex;
                 player1.averageDPS = SaveGameData.Instance.averageDPS;
                 player1.huntDPS = SaveGameData.Instance.huntDPS;
     
                 string str = JsonUtility.ToJson(this);
                 Debug.Log("str=" + str);
     
                 return str;
             }
         }

Am I missing something here? I have worked with JSON before but it's the first time that it's happening to me. Any help would be appreciated. THanks!