Fatal error: Uncaught Functional\Exceptions\InvalidArgumentException: Functional\flatten() expects parameter 1 to be array or instance of Traversable, integer given in /var/www/vhosts/smr-kutsche.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Exceptions/InvalidArgumentException.php:271
Stack trace:
#0 /var/www/vhosts/smr-kutsche.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Exceptions/InvalidArgumentException.php(69): Functional\Exceptions\InvalidArgumentException::assertCollectionAlike()
#1 /var/www/vhosts/smr-kutsche.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Flatten.php(25): Functional\Exceptions\InvalidArgumentException::assertCollection()
#2 /var/www/vhosts/smr-kutsche.de/httpdocs/includes/src/News/Category.php(300): Functional\flatten()
#3 /var/www/vhosts/smr-kutsche.de/httpdocs/includes/src/News/Controller.php(214): JTL\News\Category->getOverview()
#4 /var/www/vhosts/smr-kutsche.de/httpdocs/news.php(81): JTL\News\Controller->displayOverview()
#5 /var/www/vhosts/smr-kutsche.de/httpdocs/index.php(13): require('...')
#6 {main}
  thrown in /var/www/vhosts/smr-kutsche.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Exceptions/InvalidArgumentException.php on line 271