Typically once a year Amazon will require you to renew any third-party applications on your Seller Central account. You can renew any application on your Amazon Seller Central by navigating to Apps&Services > Manage Your Apps > Click Renew next to the Payability application.
If the API connection has been disconnected or needs to be renewed you should see the below pop-up on your Payability dashboard when you first log in:
When you click on 'Open Amazon Seller Central', you will be required to log in to Amazon with your normal Amazon login email address. Following this prompt will reestablish the API connection. Please email email@example.com once this is completed so we can ensure all applicable sales have been advanced.