Hello D.W.,
Thank you for your question about the "token expired" message. Yes, we do check this each time you come to the site. However, we aren't allowed to continually check for it. We do also check to see if it will expire in 30 days and notify you of that as well.
So, at some point after you added the snipe, some action was taken to invalidate the authorization. Most likely your eBay password was updated or changed.
Thank you for taking the time to inquire. We are happy to answer any other questions you may have.
bidslammer