php - 403 Forbidden Wordpress Database Results

I have a website, hosted on Wordpress.

I have created a custom table within the WPDB, with ARI Adminer, called 'people'. I have entered some entries for testing.

I have created a test page with the following code;

<?php
 global $wpdb;
 $roster = $wpdb->get_results($wpdb->prepare("SELECT * FROM people"));
 foreach ($roster as $people) {
   $peoplesurname = $people->Surname;
 }
?>

When I preview the page, I get:

403 Forbidden Permission denied. Our sentries tell us that you should not be here.

I am listed as an administrator, however I did not setup/install anything, I was added after setup.

I am assuming that it is an access issue to the WPDB?

Is there anywhere on the front end or in the code that I need to update to get access to the DB?

Thanks