When running this, I only get an "HTTP ERROR 500" page. As I've seen in other solutions I've added the 'index.php' before the /api section. I've also enabled WSI-Compliance mode as I've seen suggested.
<?php
$proxy = new SoapClient('http://stagingsite.club/index.php/api/v2_soap/?wsdl');
$sessionId = $proxy->login('inventory', 'password');
$result = $proxy->catalogCategoryTree($sessionId);
var_dump($result);
?>
This is how Magento documentation lists the path
$proxy = new SoapClient('http://magentohost/api/v2_soap/?wsdl');
I'd like to point out that on my web server, I do not have a similar path. I'm confused in that I don't completely understand the concept of WSDL. Is the WSDL file created, or is it an actual file that I need to find in my directory? I've ensured that SOAP is enabled.