Failure | Error Code 21916013:
ShortMessage - This Token has been revoked by App.
LongMessage - This Token has been revoked by App. The end user must complete the Auth & Auth consent flow again to generate a valid token.
Explanation and resolution:
Typically and as the error outlined, it would be triggered when the eBay token has either expired or has been revoked and you can take a look at this guide and you would be able to see the steps you can follow in order to re-authorize the instance and generate a new and valid token.