JQuery.min.js: 4 POST 500 (Internal Server Error) - php

Question

It works on localhost but not in server I. Another warning is
Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check...
Here is my form:
<form action ="" method="post" id="frmlogin" class="text" onsubmit="return flogin();">
<input type="text" name="user" id="email" placeholder="Username*" required>
<input type="password" name="pass" id="password" placeholder="Password*" required>
<input type="submit" name="login" class="login loginmodal-submit" value="Login">
Here is my Javascript:
<script>
function flogin() {
$("#errorlog").html("");
var email = document.getElementById('email').value;
var password = document.getElementById('password').value;
var request = $.ajax({
type: 'post',
url: 'action/login_action.php',
contentType: "application/json; charset=utf-8",
dataType: "json",
data: {email: email, password: password, login: "login"},
success: function (response) {
var res = parseInt(response.trim());
alert(response);
if (response.trim() == "10") {
$("#errorlog").html("Email and Password is must");
//alert(response);
}
else if (res >= 1) {
//alert(response);
document.getElementById('email').value = "";
document.getElementById('password').value = "";
window.location = "index.php";
}
else {
$("#errorlog").html("E-mail or Password is incorrect");
}
}, error: function (response) {
alert("FAIL");
alert(response);
//alert(response[0]);
//response is json you need to parse it
// var json = response,
// obj = JSON.parse(json);
// alert(response.length);
// alert(response.length);
}
});
return false;
}
</script>
The php code:
<?php
error_reporting(1);
if (!isset($_SESSION)) {
session_start();
}
require_once("../config/encrypt.php");
require_once '../config/functions.inc';
require_once '../config/database.php';
///////////////login check////////////
if ($_POST['login'] == "login") {
echo "fdgdffdf";
if (empty($_POST['password']) or empty($_POST['email'])) {
echo "10";
exit;
} else {
$en = new Encryption();
$password = trim($_POST['password']);
$email = $en->removeBadChars(trim($_POST['email']));
$db = new Database();
if ($db->open())
$password = sha1($password);
{
$sql = "select * from phpap105_signup where email='$email' and password='$password'";
// echo "select * from phpap105_signup where email='$email' and password='$password'";
//exit;
$res = mysqli_query($db->resourse(), $sql);
$cou = mysqli_num_rows($res);
if ($cou >= 1) {
$row = mysqli_fetch_array($res);
$_SESSION['client_user_id'] = $row[0];
$_SESSION['client_user_id1'] = $row[0];
$_SESSION['client_username'] = $row[1];
$_SESSION['client_logged'] = true;
// $_SESSION['adm_status'] = $row['status'];
$r = "success";
} else {
$r = "fail";
}
echo $cou;
// exit;
}
}
echo $r;
}
/////login end/////////////////
?>