Integration of myBB with website

[Matt]

Quite a bit that doesn't make sense here. You're calling this:

$user = get_user($uid);

Which should give you the user without you needing to do anything else, but $uid isn't defined anywhere.

Then this:

while ($forum_user = mysqli_fetch_array($user))

makes no sense as $user isn't a MySQL query so not sure why you're calling mysqli_fetch_array on it.

All you should need is the get_user() line, but I'm not sure if $uid needs to be passed through or where you'd get it from. I'd suggest reaching out to the MyBB Integrator author for documentation.