Last step of checkout ends with Call to undefined method error

-- url of the page with the problem -- : www.aloe-vera-fuerteventura.com
-- HikaShop version -- : 4.7.3
-- Joomla version -- : 4.3.2
-- PHP version -- : 8.1
-- Browser(s) name and version -- : Firefox, Chrome
-- Error-message(debug-mod must be tuned on) -- : Call to undefined method Joomla\CMS\Application\SiteApplication::isAdmin()

JROOT/media/com_hikashop/mail/order_creation_notification.preload.modified.php:61
2 include() JROOT/administrator/components/com_hikashop/classes/mail.php:362
3 hikashopMailClass->loadEmail() JROOT/administrator/components/com_hikashop/classes/mail.php:31
4 hikashopMailClass->get() JROOT/administrator/components/com_hikashop/classes/order.php:2075
5 hikashopOrderClass->loadOrderNotification() JROOT/administrator/components/com_hikashop/classes/order.php:442
6 hikashopOrderClass->save() JROOT/administrator/components/com_hikashop/classes/order.php:913
7 hikashopOrderClass->createFromCart() JROOT/components/com_hikashop/controllers/checkout.php:678
8 checkoutController->confirm() JROOT/libraries/src/MVC/Controller/BaseController.php:678
9 Joomla\CMS\MVC\Controller\BaseController->execute() JROOT/administrator/components/com_hikashop/helpers/helper.php:2437
10 hikashopController->execute() JROOT/components/com_hikashop/hikashop.php:88

Hello,
Call to undefined method error on checkout after last step.
See attachment for shown errors.
This issue started after Joomla update to vers 4.3.2
an identical Hikashop installation with Joomla vers 4.3.1 works fine.

Help needed, no more sales on the shop

Thomas

Hi Nicolas.
10 seconds to delete - done.
Your a genius!
Strange that the shop was running fine until this last Joomla Update.
Grateful
Thomas