wp_redirect_to_pmpro_login_after_logout.php

<?php
/**
 * Redirect to the PMPro Login page after logout.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function wp_redirect_to_pmpro_login_after_logout() {
	global $pmpro_pages;

	// Bail if PMPro is inactive or PMPro login page isn't set.
	if ( empty( $pmpro_pages ) || empty( $pmpro_pages['login'] ) ) {
		return;
	}

	// Get login page URL.
	$pmpro_login_url = get_permalink( $pmpro_pages['login'] );

	// Redirect.
	wp_safe_redirect( $pmpro_login_url );
	exit;
}
add_action( 'wp_logout', 'wp_redirect_to_pmpro_login_after_logout' );