login php

how create login with msql on traccar
i have my code not work

$email = $_POST['email'];
    $userpassword = $_POST['hashedpassword'];



	$sql = "select email,hashedpassword from users where email= '$email'  ";
	$result = mysqli_query($link,$sql);
	

	while($row = mysqli_fetch_array($result))
	{
		$data = $userpassword;
		$key = hexToStr($row['salt']);
		$hashed = hash_pbkdf2('sha1',$data, $key,1000,24,true);

		if (strToHex($hashed)==$row['hashedpassword']){
                		//session_start();
                		//$_SESSION['email'] = $email;
            		$_SESSION['hashedpassword'] = $userpassword; 
            		header('location:page.php');
             		 }
	}