Missing value [shipping]
Fix the Missing value [shipping] error in Google Merchant Center. When shipping is required, the country sub-attribute, and the account-settings alternative.
Invalid value [gtin]
Fix the Invalid value [gtin] error in Google Merchant Center. Why a GTIN is rejected, how to find the correct one, and when to remove it instead.
Missing value [shipping weight]
Fix the Missing value [shipping weight] error in Google Merchant Center. When shipping_weight is required and how to get product weights into the feed.