Redirect in PHP doesnt load my link? - php

Question

I have 2 php files.
The first one handles the link and stuff. Here is a preview my code:
<?php
session_start();
$link=$_GET['redirect'];
if ($link == '1'){
$_SESSION['link'] = 'https://www.google.com/';
header('Location: selection_handler.php');
exit;
}
if ($link == '2'){
$_SESSION['link'] = 'https://www.facebook.com/';
header('Location: selection_handler.php');
exit;
}
if ($link == '3'){
$_SESSION['link'] = 'https://www.twitter.com/';
header('Location: selection_handler.php');
exit;
}
?>
This is my selection_handler.php
<?php
session_start();
$link= $_SESSION['link'];
if(isset($_SESSION['user_id']))
{
header("Location: " .$link);
exit;
}
else
{
echo $_SESSION['link'];
}
?>
user_id would be handled later so by default, i would get the echo of the link from the session, right? that works properly but when i try to test setting a value for the user_id, i see my browser trying to load the link. It says 'Resolving host... Waiting for [insert link selected]' but doesnt fully continue to the site but instead im shown a blank page?
UPDATE: I tried changing the header to ('Location: https://www.google.com') instead of getting from the variable but im still getting a blank page