get_the_terms not working

I’ve created custom user taxonomies, I’ve got users associated with them, I can see the associations in the database, they’re editable from the user profile page, they show up in the custom taxonomy count, they’re there…

When I try to get_the_terms… nada.

Here’s what I’ve got:

$users = new WP_User_Query( array( 'role' => 'Subscriber' ) );
foreach ( $users->results as $user ) : setup_postdata($user);
                $terms = get_the_terms($user->ID, 'MyTaxonomy');
                          if ($terms) foreach ($terms as $term) {
                                       echo $term->slug . ' ';
                           }

////////// a bunch of other stuff ////////////////