Switch, splitter, hub, router

Fatal error: Uncaught TypeError: mysqli_query(): Argument #1 ($mysql) must be of type mysqli, bool given in /home/svezakuc/public_html/www/php-include/db.lib.php:707 Stack trace: #0 /home/svezakuc/public_html/www/php-include/db.lib.php(707): mysqli_query(false, 'select gitem_gd...') #1 /home/svezakuc/public_html/www/gomobile/include/ecom.lib.php(2952): dblib_get_single_column_list('select gitem_gd...') #2 /home/svezakuc/public_html/www/php-include/order.lib.php(30): find_item_delivery_places_and_methods('75039') #3 /home/svezakuc/public_html/www/html-include/gomobile/mcat.php(4): get_item_delivery_places_and_methods('75039') #4 /home/svezakuc/public_html/www/catbrowser.php(345): include_once('/home/svezakuc/...') #5 {main} thrown in /home/svezakuc/public_html/www/php-include/db.lib.php on line 707