registration as check out not possible

-- HikaShop version -- : 5.0.2 [2311290552]
-- Joomla version -- : 5.0.1
-- PHP version -- : 8.2
-- Browser(s) name and version -- : Chrome 120.0.6099.129
-- Error-message(debug-mod must be tuned on) -- : CALL TO UNDEFINED METHOD JOOMLA\CMS\APPLICATION\SITEAPPLICATION::ISADMIN()

unpossible to make new registration for new users as checkout