You revoked your authorization at eBay for us to bid on your behalf. Please visit your Preferences and click 'Renew Authorization'.
How to fix this?

Hello Walter,
Thank you for your question about this snipe. When we placed your snipe, eBay returned the error, "This Token has been revoked by App." It appears that you revoked our authorization at some point in the past. (We did not take this action.)
To renew your authorization, just visit the BidSlammer Preferences page and follow the prompt to "Refresh Your Authorization."
Authentication can only be revoked by from your "My eBay" page (My eBay > Account tab > Site Preferences > Third Party Authorizations > Show).
We hope we have resolved this to your satisfaction. Please advise if we can help with anything else.