Fatal error: Uncaught Error: Call to undefined function register_api_field() in /var/www/mainsite/wordpress/wp-content/plugins/acf-to-wp-api/acf-to-wp-api.php:221 Stack trace: #0 /var/www/mainsite/wordpress/wp-includes/class-wp-hook.php(286): ACFtoWPAPI->addACFDataPostV2(Object(WP_REST_Server)) #1 /var/www/mainsite/wordpress/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) #2 /var/www/mainsite/wordpress/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #3 /var/www/mainsite/wordpress/wp-includes/rest-api.php(432): do_action('rest_api_init', Object(WP_REST_Server)) #4 /var/www/mainsite/wordpress/wp-includes/rest-api.php(259): rest_get_server() #5 /var/www/mainsite/wordpress/wp-includes/class-wp-hook.php(286): rest_api_loaded(Object(WP)) #6 /var/www/mainsite/wordpress/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters('', Array) #7 /var/www/mainsite/wordpress/wp-includes/plugin.php(515): WP_Hook->do_action(Array) #8 /var/www/mainsite/wordpress/wp-includes/class-wp.php(373): do_action_ref_a in /var/www/mainsite/wordpress/wp-content/plugins/acf-to-wp-api/acf-to-wp-api.php on line 221