Problem using WWW with PHP and MYSQL

I've set up a MySQL database, PHP script, and a C# script to try and setup a registration service. The database seems to be working correctly. When I access my PHP script through my browser it works correctly creating a username and password in my MySQL database. When I run my C# script through unity however it does not create a username or password at all. I cannot find what the issue would be if someone could help me out id be very appreciative.

PHP code:

     $username = $_POST["usernamePost"];
     $password = $_POST["passwordPost"];
     
     //Make Connection
     $connection = new mysqli($servername, $serverusername, $serverpassword, $serverdatabasename);
     
     //Check Connection
     if(!$connection){
         die("Connection failed. ". mysqli_connect_error());
     }
     
     $check = "SELECT * FROM accounts WHERE `username`='".$username."'";
     $result = mysqli_query($connection , $check);    
     $numrows = mysqli_num_rows($result);
     if ($numrows == 0)
     {
         $pass = md5($password);
         $ins = "INSERT INTO accounts (`username` ,  `password`) VALUES ('".$username."' ,  '".$password."')";
         $result = mysqli_query($connection , $ins);    
         if ($result)
             die ("Successfully Created User!");
         else
             die ("Error: ");
     }
     else
     {
         die("User already exists!");
     }
 ?>

C# Script: using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI;

 public class DataInserter : MonoBehaviour {
 
     public InputField inputUsername;
     public InputField inputPassword;
 
     string createUserURL = "http://localhost/NewUser.php";
 
     // Use this for initialization
     void Start () {
         
     }
     
     // Update is called once per frame
     void Update () {
         if (Input.GetKeyDown(KeyCode.Space)) Register(inputUsername.text, inputPassword.text);
     }
 
     public void Register(string username, string password)
     {
         StartCoroutine(CreateUser(username, password));
     }
 
 
     IEnumerator CreateUser(string username, string password)
     {
         WWWForm form = new WWWForm();
         form.AddField("usernamePost", username);
         form.AddField("passwordPost", password);
 
         WWW www = new WWW(createUserURL, form);
         Debug.Log(www.error);
         Debug.Log(www.text);
         yield return www;
         if (www.error != null)
         {
             Debug.Log("Something went wrong");
         }
     }
 }