Fatal error: Uncaught Functional\Exceptions\InvalidArgumentException: Functional\flatten() expects parameter 1 to be array or instance of Traversable, integer given in /var/www/vhosts/pro-schlafen.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Exceptions/InvalidArgumentException.php:272
Stack trace:
#0 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Exceptions/InvalidArgumentException.php(70): Functional\Exceptions\InvalidArgumentException::assertCollectionAlike()
#1 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Flatten.php(26): Functional\Exceptions\InvalidArgumentException::assertCollection()
#2 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/src/Link/LinkGroup.php(136): Functional\flatten()
#3 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/src/Link/LinkGroupList.php(200): JTL\Link\LinkGroup->map()
#4 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/src/Link/LinkGroupList.php(92): JTL\Link\LinkGroupList->loadDefaultGroups()
#5 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/src/Services/JTL/LinkService.php(97): JTL\Link\LinkGroupList->loadAll()
#6 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/src/Services/JTL/LinkService.php(51): JTL\Services\JTL\LinkService->initLinkGroups()
#7 [internal function]: JTL\Services\JTL\LinkService->__construct()
#8 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/vendor/illuminate/container/Container.php(877): ReflectionClass->newInstanceArgs()
#9 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/vendor/illuminate/container/Container.php(714): Illuminate\Container\Container->build()
#10 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/vendor/illuminate/container/Container.php(284): Illuminate\Container\Container->resolve()
#11 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/vendor/illuminate/container/Container.php(829): Illuminate\Container\Container->Illuminate\Container\{closure}()
#12 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/vendor/illuminate/container/Container.php(714): Illuminate\Container\Container->build()
#13 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/vendor/illuminate/container/Container.php(661): Illuminate\Container\Container->resolve()
#14 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/src/Services/Container.php(101): Illuminate\Container\Container->get()
#15 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/src/Session/Frontend.php(274): JTL\Services\Container->getLinkService()
#16 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/src/Session/Frontend.php(91): JTL\Session\Frontend->updateGlobals()
#17 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/src/Session/Frontend.php(63): JTL\Session\Frontend->setStandardSessionVars()
#18 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/src/Session/Frontend.php(49): JTL\Session\Frontend->__construct()
#19 /var/www/vhosts/pro-schlafen.de/httpdocs/includes/globalinclude.php(119): JTL\Session\Frontend::getInstance()
#20 /var/www/vhosts/pro-schlafen.de/httpdocs/index.php(6): require('...')
#21 {main}
thrown in /var/www/vhosts/pro-schlafen.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Exceptions/InvalidArgumentException.php on line 272