The problem after installing
If you encounter a problem like this one
Or
Installing data... PHP Fatal error: Declaration of MGS\Mpanel\Helper\Swatches\Data::getProductMediaGallery(Magento\Catalog\Model\Product $product) must be compatible with Magento\Swatches\Helper\Data::getProductMediaGallery(Magento\Catalog\Model\Product $product): array in /home/cloudpanel/htdocs/www.abacionline.com/app/code/MGS/Mpanel/Helper/Swatches/Data.php on line 148 {"messages":{"error":[{"code":500,"message":"Fatal Error: 'Declaration of MGS\\Mpanel\\Helper\\Swatches\\Data::getProductMediaGallery(Magento\\Catalog\\Model\\Product $product) must be compatible with Magento\\Swatches\\Helper\\Data::getProductMediaGallery(Magento\\Catalog\\Model\\Product $product): array' in '\/home\/cloudpanel\/htdocs\/www.abacionline.com\/app\/code
This problem occurs once you didn't apply a patch for Magento version you are using, please refer our document to apply the patch for Magento version you are using, the problem will be resolved
https://www.magesolution.com/themes/claue/docs/m2/index.html#install-theme
Please note: You also need to read the file "readme.txt" in the patch as well