If you've had an account with ShippingEasy for a while, our authorization as a developer might have expired. It happens after a certain amount of time and you may have gotten an email to your Amazon seller account notifying you that your API tokens are expiring. You will need to re-authorize your MWS Developer Permission.
To renew authorization for ShippingEasy to Access Amazon:
- Navigate to this URL: https://sellercentral.amazon.com/gp/account-manager/ home.html/ref=au_userperms_dnav_xx_
- In the top right corner, go to Settings and select User Permissions:
- Under "Amazon MWS Developer Permissions" select to "Renew Access" on each relevant developer access.