Fatal error Backoffice

Calling a gallery in the admin area leads to fatal error
Frontend works properly

WP Version 6.1.1
Photo Gallery by Supsystic Version 1.15.12
PHP-Version 8.1.14

Fatal error: Uncaught TypeError: Unsupported operand types: string * int in /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/uploads/grid-gallery/cache/twig/5e/5ef836b90f3c4079825478d079a8608dfdfc2a09ddc972cbfb9980ca4575ce0d.php:2805 Stack trace: #0 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Twig/Template.php(215): __TwigTemplate_b3d0bf8d24e617f5eec1ff5d3e393707dc0953e9ce9af70c827ea3e8c87c099d->block_modals(Array, Array) #1 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/uploads/grid-gallery/cache/twig/5e/5ef836b90f3c4079825478d079a8608dfdfc2a09ddc972cbfb9980ca4575ce0d.php(1256): Twig_SupTwgSgg_Template->displayBlock(‘modals’, Array, Array) #2 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Twig/Template.php(215): __TwigTemplate_b3d0bf8d24e617f5eec1ff5d3e393707dc0953e9ce9af70c827ea3e8c87c099d->block_content(Array, Array) #3 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/uploads/grid-gallery/cache/twig/92/9209492f4e216b9c8306c87c5d79150b4c0e0bb5c7a54581b99146ee8d573ee3.php(163): Twig_SupTwgSgg_Template->displayBlock(‘content’, Array, Array) #4 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Twig/Template.php(432): __TwigTemplate_29ea4fd0e86bcbc2cadc4812bbf0b82c6b5d1f1d2c3975ceb63461802fd94f50->doDisplay(Array, Array) #5 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Twig/Template.php(403): Twig_SupTwgSgg_Template->displayWithErrorHandling(Array, Array) #6 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/uploads/grid-gallery/cache/twig/5e/5ef836b90f3c4079825478d079a8608dfdfc2a09ddc972cbfb9980ca4575ce0d.php(73): Twig_SupTwgSgg_Template->display(Array, Array) #7 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Twig/Template.php(432): __TwigTemplate_b3d0bf8d24e617f5eec1ff5d3e393707dc0953e9ce9af70c827ea3e8c87c099d->doDisplay(Array, Array) #8 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Twig/Template.php(403): Twig_SupTwgSgg_Template->displayWithErrorHandling(Array, Array) #9 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Twig/Template.php(411): Twig_SupTwgSgg_Template->display(Array) #10 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Twig/Environment.php(362): Twig_SupTwgSgg_Template->render(Array) #11 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Rsc/Mvc/Controller.php(62): Twig_SupTwgSgg_Environment->render(‘@galleries/sett…’, Array) #12 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/src/GridGallery/Core/BaseController.php(41): RscSgg_Mvc_Controller->response(‘@galleries/sett…’, Array) #13 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/src/GridGallery/Galleries/Controller.php(793): GridGallery_Core_BaseController->response(‘@galleries/sett…’, Array) #14 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Rsc/Mvc/Module.php(164): GridGallery_Galleries_Controller->settingsAction(Object(RscSgg_Http_Request)) #15 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/plugins/gallery-by-supsystic/vendor/Rsc/Resolver.php(229): RscSgg_Mvc_Module->handle() #16 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-includes/class-wp-hook.php(308): RscSgg_Resolver->resolve(”) #17 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(”, Array) #18 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #19 /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-admin/admin.php(259): do_action(‘toplevel_page_s…’) #20 {main} thrown in /homepages/7/d17352219/htdocs/tanz-um-die-ecke/www/wp-content/uploads/grid-gallery/cache/twig/5e/5ef836b90f3c4079825478d079a8608dfdfc2a09ddc972cbfb9980ca4575ce0d.php on line 2805