Mysql PDO Register user insert not inserting, no error feedback

Hello, I have my connection to database working, as i can check if a username already exists in my database, i also have populated a drop down list with options from my database, my issue is with registering a new user i.e. inserting the $_POST data into my table.

PHP is not sending an error i can research, i have tried the binding values method of PDO with no luck.Also strangely earlier i got a my php file to echo 0 at the files end an execute my debug.log for user added in my c# as www.text = 0 (see code), but no user was actually added to my database. Now i am stuck with no user insert, no error data from the php file to www.text, I have tried all day. Any help would be appreciated.

Here is the relevant code:

MYSQL TABLE:

 CREATE TABLE `players` (
   `id` int(10) NOT NULL,
   `country_id` smallint(11) UNSIGNED NOT NULL,
   `language_id` smallint(11) UNSIGNED NOT NULL,
   `first_name` varchar(50) CHARACTER SET utf8 NOT NULL,
   `last_name` varchar(50) CHARACTER SET utf8 NOT NULL,
   `email` varchar(40) COLLATE utf8_unicode_ci NOT NULL,
   `username` varchar(16) COLLATE utf8_unicode_ci NOT NULL,
   `hash` varchar(100) COLLATE utf8_unicode_ci NOT NULL,
   `salt` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
   `password_hint` text CHARACTER SET utf8 NOT NULL,
   `score` int(10) NOT NULL DEFAULT '0'
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

 ALTER TABLE `players`
   ADD PRIMARY KEY (`id`),
   ADD UNIQUE KEY `username` (`username`),
   ADD KEY `country_id` (`country_id`),
   ADD KEY `language_id` (`language_id`);

CONNECT.PHP:

 <?php
 $host ='localhost';
 $user ='XYZ';
 $dbpassword = 'XYZ';
 $dbname = 'XYZ';
 
 //Set DSN
 
 $dsn = 'mysql:host='. $host.';dbname='. $dbname;
 
 //create PDO instance
 
 $pdo = new PDO($dsn, $user, $dbpassword);
 $pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_OBJ);
 $pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);

  // THIS ERROR MODE IS ON
 $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
  ?>

PHP CODE: register.php

  <?php
         
         require 'connect.php'; //WORKING
         
         $first_name = $_POST["first_name"];
         $last_name = $_POST["last_name"];
         $username = $_POST["username"];
         $password = $_POST["password"];
         $password_hint = $_POST["password_hint"];
         //input from dropdowns
         $country_id = $_POST['country'];
         $language_id = $_POST['language'];
         
         $namecheckquerry = 'SELECT username FROM players WHERE username = ?';
         $stmt = $pdo->prepare($namecheckquerry);
         $stmt->execute([$username]);
         $nameCount = $stmt->rowCount();
         
         if($nameCount > 0){
           echo "3. A player with that Username already exists";
           exit();
         }
         
         //add user to table
         
         $salt = "\$5\$rounds=5000\$". "andrewjackson" . $username ."\$";
         $hash  = crypt($password, $salt);
         
         $insertuserqry = 'INSERT INTO players(first_name, last_name, username, hash, salt) 
                                        VALUES (:first_name, :last_name, :username, :hash, :salt)';
         $stmt = $pdo->prepare($insertuserqry);

          // ERROR STATEMENT NOT SENDING TO WWW.TEXT
          if (!$stmt) {
              echo "\nPDO::errorInfo():\n";
              print_r($dbh->errorInfo());
           }

         $stmt->execute(['first_name'=> $first_name , 'last_name'=> $last_name , 'username'=> 
         $username, 'hash'=> $hash, 'salt'=> $salt]);
         
         echo '0';
         
         ?>

C# CODE:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 
 public class registerme_new : MonoBehaviour
 {
  
 
 
     public InputField firstnamefield;
     public InputField lastnamefield;
     public InputField usernamefield;
     public InputField passwordfield;
     public InputField passwordhintfield;
     public Dropdown countryField;
     public Dropdown languageField;
     public Text text;
 
 
 
     public Button submitButton;
 
     IEnumerator Start ()
     {

         //Connect to Database and get list of possible player registration countries
         WWW countryRequest = new WWW("http://www.mysite.com/get_country_list.php");
         yield return countryRequest;
         //string[] webResults = countryRequest.text.Split(',');
         List<string> countryList = new List<string>(countryRequest.text.Split(','));
         countryField.AddOptions(countryList);
 
   
         //Connect to Database and get list of possible player languages
         WWW languageRequest = new WWW("http://www.mysite.com/get_language_list.php");
         yield return languageRequest;
         //string[] webResults = languageRequest.text.Split(',');
         List<string> languageList = new List<string>(languageRequest.text.Split(','));
         languageField.AddOptions(languageList);
 
     }
     
 
     public void CallRegister() {
         StartCoroutine(Register());
 
     }
     IEnumerator Register()
     {
 
     
 
         WWWForm form = new WWWForm();
         form.AddField("country", countryField.value);
         form.AddField("language", languageField.value);
         form.AddField("first_name", firstnamefield.text);
         form.AddField("last_name", lastnamefield.text);
         form.AddField("username", usernamefield.text);
         form.AddField("password", passwordfield.text);
         form.AddField("password_hint", passwordhintfield.text);
        
         WWW www = new WWW("http://www.mysite.com/register.php", form);
         yield return www; 
 
      if (www.text == "0")
        {
            Debug.Log("User created succesfully");
            UnityEngine.SceneManagement.SceneManager.LoadScene(0);
         }
       else {
           // THIS IS THE ERROR I AM GETTING WITH NOTHING FROM WWW.TEXT
           Debug.Log("User creation failed. Error #"+ www.text);
       }
 
     }
 
 
 }