Limit subsite access to specific membership levels

my_pmpro_subsite_require_membership_level.php

<?php // copy from below
/**
 * This recipe redirects members without the specified levels away from subsite pages
 * to a page on the main network site
 *
 * This recipe has to be added to a customization plugin that is only active 
 * on a subsite where you would like to enforce this redirection (Not network activated)
 *
 * Read this companion article for step-by-step directions:
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/#method-2
 *
 */
function my_pmpro_subsite_require_membership_level() {

	// bail if not on a multisite env, or PMPro not active
	if ( ! is_multisite() || ! function_exists( 'pmpro_hasmembershiplevel' ) ) {
		return;
	}

	global $current_site;
	$primary_network_site = $current_site;
	$primary_network_site_url = get_home_url( $primary_network_site->id );

	/*
		Set an optional landing page slug,
		e.g. $landing_page_slug = '/membership-account/membership-levels/';
	*/
	$landing_page_slug = '';

	// set redirect url
	$redirect_url = $primary_network_site_url . $landing_page_slug;

	// membership level IDs allowed to access to this subsite
    $allowed_levels = array( 1, 2 ); 
	
	if ( ! is_admin() && ! pmpro_hasMembershipLevel( $allowed_levels ) ) {
		wp_redirect( $redirect_url );
		exit;
	}
}
add_action( 'template_redirect', 'my_pmpro_subsite_require_membership_level' );