PHP - Code Does Not Return Any Results

Hi,

For about a month, I have been trying to figure out why my code will not return anything after posting a wwwForm (I have also tried the newer equivalent of this function but I had no luck with that either.) The nameField and passwordField are taken from text boxes within the game and the code used in my login script is copied and pasted from a Register script but I have changed the file location to the login.php file. The register script works fine and I can add new users to my database but the login script only outputs "Form Sent." and not the "present" that should return when the form is returned and it never gets any further than that point meaning that it lets the user through with no consequence if they use an invalid name because the script never returns an answer. What should I do to fix this?

Thanks,

Unity Code:

using System.Collections;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.Networking;

public class Login : MonoBehaviour
{
    public InputField nameField;
    public InputField passwordField;

    public Button acceptSubmissionButton;

    public void CallLogInCoroutine()
    {
        StartCoroutine(LogIn());
    }

    IEnumerator LogIn()
    {
        WWWForm form = new WWWForm();
        form.AddField("username", nameField.text);
        form.AddField("password", passwordField.text);
        WWW www = new WWW("http://localhost/sqlconnect/login.php", form);
        Debug.Log("Form Sent.");
        yield return www;
        Debug.Log("Present");        if (www.text[0] == '0')
        {
            Debug.Log("Present2");
            DatabaseManager.username = nameField.text;
            DatabaseManager.score = int.Parse(www.text.Split('\t')[1]);
            Debug.Log("Log In Success.");
        }
        else
        {
            Debug.Log("User Login Failed. Error #" + www.text);
        }
        
    }

    public void Validation()
    {
        acceptSubmissionButton.interactable = nameField.text.Length >= 7 && passwordField.text.Length >= 8;
    }
}

login.php:

<?php
    echo "Test String2";
    $con = mysqli_connect('localhost', 'root', 'root', 'computer science coursework');

    // check for successful connection.
    if (mysqli_connect_errno())
        {
            echo "1: Connection failed"; // Error code #1 - connection failed.
            exit();
        }

    $username = mysqli_escape_string($con, $_POST["username"]);
    $usernameClean = filter_var($username, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_LOW | FILTER_FLAG_STRIP_HIGH);
    $password = $_POST["password"];

    if($username != $usernameClean)
    {
        echo "7: Illegal Username, Potential SQL Injection Query. Access Denied.";
        exit();
    }

    // check for if the name already exists.

    $namecheckquery = "SELECT username, salt, hash, score FROM players WHERE username='" . $usernameClean . "';";

    $namecheck = mysqli_query($con, $namecheckquery) or die("2: Name check query failed"); // Error code # 2 - name check query failed.

    if (mysqli_num_rows($namecheck) != 1)
    {
    	echo "5: No User With Your Log In Details Were Found Or More Than One User With Your Log In Details Were Found"; // Error code #5 - other than 1 user found with login details
    	exit();
    }

    // get login info from query
    $existinginfo = mysqli_fetch_assoc($namecheck);
    $salt = $existinginfo["salt"];
    $hash = $existinginfo["hash"];

    $loginhash = crypt($password, $salt);
    if ($hash != $loginhash)
    {
    	echo "6: Incorrect Password"; // error code #6 - password does not hash to match table
    	exit;
    }
    echo "Test String2";
    echo"0\t" . $existinginfo["score"];

?>

case "update-delete":
	if(isset($_POST['highlight-purchased'])) 
		{
			// ****** Setup customized query to obtain only items that are checked ******
			$sql = "SELECT * FROM shoplist WHERE";
					for($i=0; $i < count($_POST['checkboxes']); $i++)
						{
							$sql=$sql . " idnumber=" . $_POST['checkboxes'][$i] . " or";
						}
					$sql= rtrim($sql, "or");
											
			$statement = $conn->prepare($sql);
			$statement->execute();
																						
			// *** fetch results for all checked items (1st query) *** //
			$result = $statement->fetchAll();

			$statement->closeCursor();
											
			// Setup query that will change the purchased flag to "N", if it's currently set to "Y"
			$sqlSetToN = "UPDATE shoplist SET purchased = 'N' WHERE purchased = 'Y'";
											
			// Setup query that will change the purchased flag to "Y", if it's currently set to "N", "", or NULL
			$sqlSetToY = "UPDATE shoplist SET purchased = 'Y' WHERE purchased = 'N' OR purchased = '' OR purchased IS NULL";

			$statementSetToN = $conn->prepare($sqlSetToN);
			$statementSetToY = $conn->prepare($sqlSetToY);
											
			/*** loop through the results/collection of checked items ***/
			foreach($result as $row)
				{
					if ($row["purchased"] != "Y")
						{
							// *** fetch one row at a time pertaining to the 2nd query *** //
							$resultSetToY = $statementSetToY->fetch();
															
							foreach($resultSetToY as $row)
								{															
									$statementSetToY->execute();																
								}
						}
					else
						{
							// *** fetch one row at a time pertaining to the 2nd query *** //
							$resultSetToN = $statementSetToN->fetch();
															
							foreach($resultSetToN as $row)
								{															
									$statementSetToN->execute();																
								}
						}
				}
				break;
		}