Fatal error: Uncaught TypeError: Argument 1 passed to Magento\Catalog\Model\ProductRepository::prepareSku() must be of the type string, null given, called in /domains/omorovicza.com/http/vendor/magento/module-catalog/Model/ProductRepository.php on line 856 and defined in /domains/omorovicza.com/http/vendor/magento/module-catalog/Model/ProductRepository.php:866 Stack trace: #0 /domains/omorovicza.com/http/vendor/magento/module-catalog/Model/ProductRepository.php(856): Magento\Catalog\Model\ProductRepository->prepareSku(NULL) #1 /domains/omorovicza.com/http/vendor/magento/module-catalog/Model/ProductRepository.php(329): Magento\Catalog\Model\ProductRepository->saveProductInLocalCache(Object(Magento\Catalog\Model\Product\Interceptor), '7a256beb77cd513...') #2 /domains/omorovicza.com/http/vendor/magento/module-catalog/Model/ProductRepository.php(294): Magento\Catalog\Model\ProductRepository->cacheProduct('7a256beb77cd513...', Object(Magento\Catalog\Model\Product\Interceptor)) #3 /domains/omorovicza.com/http/generated/code/Mag in /domains/omorovicza.com/http/vendor/magento/module-catalog/Model/ProductRepository.php on line 866