In order to ensure that your Amazon Connection with ShippyPro is always working, you need to refresh the Token when it get expired.
This action will require just a few minutes!
What you need to do
Here the instructions you have to follow in order to refresh the token:
Login to your Seller Central account
Navigate to App and Services > Manage your App
Search for ShippyPro on the list and click on Re-Authorized
That is all!