Merge pull request #465 from brezden/patch-1

Update set-billing-address.md

Author: keharper

src/pages/graphql/schema/cart/mutations/set-billing-address.md

@@ -109,3 +109,18 @@ mutation {
   }
 }
 ```
+
+## Errors
+
+Error | Description
+--- | ---
+`Could not find a cart with ID "XXX"` | The specified `cart_id` value does not exist in the `quote_id_mask` table.
+`Required parameter "cart_id" is missing` | The `cart_id` argument was omitted or contains an empty value.
+`Required parameter "billing_address" is missing` | The `billing_address` argument was omitted or contains an empty array.
+`The billing address must contain either "customer_address_id", "address", or "same_as_shipping".` | The billing address input object must include at least one of the following fields: `customer_address_id`, `address`, or `same_as_shipping`.
+`The billing address cannot contain "customer_address_id" and "address" at the same time.` | The billing address input contains both `customer_address_id` and `address`. Only one can be used.
+`Could not use the "same_as_shipping" option, because multiple shipping addresses have been set.` | The `same_as_shipping` option was provided, but the cart has multiple shipping addresses, making this option invalid.
+`Could not use the "same_as_shipping" option, because the shipping address has not been set.` | The `same_as_shipping` option was provided, but no valid shipping address exists on the cart.
+`Could not use the "use_for_shipping" option, because multiple shipping addresses have already been set.` | The `use_for_shipping` flag was provided, but the cart already has multiple shipping addresses.
+`The current customer isn't authorized.` | An unauthorized user (guest) tried to set a billing address on behalf of an authorized user (customer), or a customer tried to set a billing address on behalf of another customer.
+`An error occurred while processing the billing address.` | The billing address could not be validated. One or more required fields may be missing or invalid.