Best Free WordPress Booking Plugin for Small Businesses (No WooCommerce Needed)

Fatal error: Uncaught TypeError: sizeof(): Argument #1 ($value) must be of type Countable|array, string given in /home/wpbookinglysumon/public_html/wp-content/plugins/service-booking-manager/inc/MPWPB_Function.php:202 Stack trace: #0 /home/wpbookinglysumon/public_html/wp-content/plugins/service-booking-manager/templates/registration/static_registration.php(17): MPWPB_Function::get_all_service() #1 /home/wpbookinglysumon/public_html/wp-content/plugins/service-booking-manager/Frontend/MPWPB_Shortcodes.php(33): include('/home/wpbooking...') #2 /home/wpbookinglysumon/public_html/wp-includes/shortcodes.php(434): MPWPB_Shortcodes->service_booking() #3 [internal function]: do_shortcode_tag() #4 /home/wpbookinglysumon/public_html/wp-includes/shortcodes.php(273): preg_replace_callback() #5 /home/wpbookinglysumon/public_html/wp-includes/class-wp-hook.php(341): do_shortcode() #6 /home/wpbookinglysumon/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters() #7 /home/wpbookinglysumon/public_html/wp-includes/post-template.php(256): apply_filters() #8 /home/wpbookinglysumon/public_html/wp-content/themes/bookingly/single.php(36): the_content() #9 /home/wpbookinglysumon/public_html/wp-includes/template-loader.php(132): include('/home/wpbooking...') #10 /home/wpbookinglysumon/public_html/wp-blog-header.php(19): require_once('/home/wpbooking...') #11 /home/wpbookinglysumon/public_html/index.php(17): require('/home/wpbooking...') #12 {main} thrown in /home/wpbookinglysumon/public_html/wp-content/plugins/service-booking-manager/inc/MPWPB_Function.php on line 202