Do you support the Amazon PAAPI (Product Advertising API) v5.0?
Amazon recently (in January/February 2020) sent an email to announce that they are soon upgrading their API to version 5.
Fresh Store and OneAzon have already been updated to use this version (back in October 2019) and there is nothing you need to do (except make sure you are using the latest version!).
The Amazon API is also known as the PAAPI (Product Advertising API).
If you have any questions, please drop a message to support.