Metabox and REST API

/* Disable REST API when not logged in */
add_filter( 'rest_authentication_errors', 'chuck_disable_rest_endpoints' );
function chuck_disable_rest_endpoints( $access ) {
    if( ! is_user_logged_in() ) {
        return new WP_Error( 'rest_cannot_access', __( 'Only authenticated users can access the REST API.', 'disable-json-api' ), array( 'status' => rest_authorization_required_code() ) );
    }
  return $access;
}


/* Client to Voyage Metabox Relationship */
add_action( 'mb_relationships_init', 'wvm_client_to_voyage_connection' );
function wvm_client_to_voyage_connection() {
    MB_Relationships_API::register( [
        'id'   => 'client-to-voyage-relationship',
        'from' => [
            'object_type' => 'user',
            'meta_box'    => [
                'title' => 'My Voyage(s)',
            ],
            'field' => array(
                'max_clone' => -1,
                'query_args' => array(
                    'role__in' => array( 'client' )
                )
            )
        ],
        'to'   => [
            'object_type' => 'post',
            'post_type'   => 'voyage',
            'meta_box'    => [
                'title' => 'Client',
            ],
        ],
    ] );
}

/* Shortcode to show upcoming voyages for a client */
function fdm_my_voyages_shortcode() {
    if ( is_user_logged_in() ) {

        $voyages = MB_Relationships_API::get_connected( [
            'id'   => 'client-to-voyage-relationship',
            'from' => get_current_user_id(),
        ] );

        if ( ! $voyages ){
            return 'No trips assigned.';
        }
        $output = '';
        $output .= '<div class="client-voyages">';
        $i = 0;
        foreach( $voyages as $voyage){
            $voyageID = $voyage->ID;
            $url = site_url( 'wp-json/wp/v2/voyage/' ) . $voyageID;
            $response = wp_remote_get( $url );

            // Exit if error.
            if ( is_wp_error( $response ) ) {
                return;
            }
            $posts = json_decode( wp_remote_retrieve_body( $response ) );
            $startDate = $posts->meta_box->trip_start_date;
            $startDate = date("M d", strtotime($startDate));
            $endeDate = $posts->meta_box->trip_end_date;
            $endeDate = date("M d", strtotime($endeDate));
            $voyageLink = $posts->link;

            $output .= '<a class="client-voyage-link" href="'.$voyageLink.'">';
            $output .= '<div class="client-voyage">'.$voyage->post_title.'</div>';
            $output .= '<div class="client-voyage-dates">'.$startDate.' - '.$endeDate.'</div>';
            $output .= '</a>';
        }
        $output .= '</div>';
        return $output;
    } else {
        $output .= 'No Access!';
    }
}