Auth token is hard expired
The error message "Auth token is hard expired, User needs to generate a new token for this application." means that token (unique key for using ebay account to list/relist data, get orders, etc.) becomes expired and PrestaBay application can't use to perform any actions with ebay. The solution for this is re-assign ebay account.
In order to do this, please:
1) go to page Catalog->eBay->Accounts
2) Click on Account edit
3) Click on the button "Connect to Ebay account"
4) Log in to ebay and grand access to PrestaBay