Fatal error: Uncaught TypeError: Argument 1 passed to Magento\Catalog\Model\ProductRepository::prepareSku() must be of the type string, null given, called in /data02/virt55079/domeenid/www.arsi.ee/htdocs/vendor/magento/module-catalog/Model/ProductRepository.php on line 790 and defined in /data02/virt55079/domeenid/www.arsi.ee/htdocs/vendor/magento/module-catalog/Model/ProductRepository.php:800 Stack trace: #0 /data02/virt55079/domeenid/www.arsi.ee/htdocs/vendor/magento/module-catalog/Model/ProductRepository.php(790): Magento\Catalog\Model\ProductRepository->prepareSku(NULL) #1 /data02/virt55079/domeenid/www.arsi.ee/htdocs/vendor/magento/module-catalog/Model/ProductRepository.php(349): Magento\Catalog\Model\ProductRepository->saveProductInLocalCache(Object(Magento\Catalog\Model\Product\Interceptor), '70f219631131d9b...') #2 /data02/virt55079/domeenid/www.arsi.ee/htdocs/vendor/magento/module-catalog/Model/ProductRepository.php(314): Magento\Catalog\Model\ProductRepository->cacheProduct('70f219631131d9b...', Object(Magento\C in /data02/virt55079/domeenid/www.arsi.ee/htdocs/vendor/magento/module-catalog/Model/ProductRepository.php on line 800