PHP Session 5.4 to 5.6 - php

Question

I have created a website lately with a group of students, but were having some troubles.
We created the website in php 5.4 on a localhost and it worked perfectly.
But now we wanted to get the site online and the webhosting is using a different version of php(5.6).
So now the session does not start.
It redirects us to the homepage, but we are not logged in.
We were thinking that it was because of the version of php, since it did work at first.
<?php
include_once 'connect.php';
session_start();// Starting Session
// Storing Session
$user_check=$_SESSION['gebruiker'];
// SQL Query To Fetch Complete Information Of User
$ses_sql="select email_adres from gebruiker where email_adres='".$user_check".'";
$row = mysqli_fetch_assoc($ses_sql);
$login_session =$row['username'];
if(!isset($login_session)){
header('Location: login.php'); // Redirecting To Home Page
}
else{
header('Location: acountgegevens.php');
}
?>
<?php
include_once 'connect.php';
function logincheck(){
if(isset($_POST['submit'])){
$error = 0;
// declare variables
$email = null;
$password = null;
// check if email address has been set
if (isset($_POST['email_adres']) &&
!empty($_POST['email_adres'])) {
$email = addslashes($_POST['email_adres']);
}
// check if password has been set
if (isset($_POST['password']) && !empty($_POST['password'])) {
$password = md5($_POST['password']);
}
if ($email == null || $password == null) {
$error = 1;
}
// query database for user credentials
$db = new PDO('**');
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$statement = $db->prepare("SELECT *
FROM gebruiker
WHERE email_adres = :email
AND wachtwoord = :password
LIMIT 1");
$statement->execute(array(':email' => $email, ':password' => $password));
$result = $statement->fetch(PDO::FETCH_OBJ);
if (!$result) {
$error = 1;
} else {
session_start();
$_SESSION['gebruiker'] = $email;
var_dump($_SESSION);
?>
<script>location.href='index.php'</script>
<?php
}
return $error;
}
}
?>
These two files are included, but we cant figure it out.
Could someone help?

Answer 1

I would hazzard a guess that your connect.php has not been changed to match the hosting companies host/user/password and therefore is outputting an error message.
This of course means that session_start() , which was placed after the connect.php and therefore after your script has attempted to send something to the browser, will not work.
You are only seeing the result of the failed session_start() but I would check the connect.php is configured correctly for its new hosting location