No metabox on user profile

I’ve added a snippet to connect users to my custom post type “program”. The meta box can be seen on programs and connections made/saved, but there is no meta box on user profile pages. What am I missing?

add_action( 'mb_relationships_init', function() {
    MB_Relationships_API::register( array(
        'id'   => 'users_to_programs',
        'from' => array(
            'object_type' => 'user',
            'meta_box'    => array(
                'title'       => 'Program',
                'context'       => 'normal',
            ),
        ),
        'to'   => array(
            'object_type' => 'post',
            'post_type'   => 'program',
            'meta_box'    => array(
                'title'         => 'Program Followers',
                'context'       => 'side',
                'empty_message' => 'No users',
            ),
        ),
    ) );

} );