Found the solution. Solution at the bottom of the post
I have some code in php using sessions (I'm just testing them out - I want to use them in a login system).
test1.php:
<?php
session_start();
$_SESSION["test"] = "works";
echo $_SESSION["test"];
?>
test2.php:
<?php
echo $_SESSION["test"];
?>
test1.php output the correct value (where I wrote echo $_SESSION["test"];), however when I switch to test2.php, there's nothing. I have checked the cookies (both websites have the same session cookie). Could the problem be a server error?
Found the solution. A simple error like that can create a big problem. At the time, I did not realize that I had to have a session_start() at the beginning of every php webpage that I used session variables in.
There must be a sesssion_start(); at the beginning of EVERY php webpage that you are using session variables in