On April 5 2021, Support for Showcase Shopping Ads Will Be Removed from the AdWords API
https://ads-developers.googleblog.comOn April 5, 2021, support for Showcase Shopping ads will be removed from the AdWords API. Users will no longer be able to create or update the following Showcase Shopping objects, and attempts to do so will result in an error.
This change only affects AdWords API users. Management of Showcase Shopping ads is not supported by Google Ads API or Google Ads scripts.