Hi Community,
Update - We were able to touch base with eBay about this situation and the posting failures we are seeing from our site are apparently related to a technical issue on their end that is causing some users to be unable to sign in to eBay and Paypal as well, which they have posted about on the following thread of their announcements board: http://www2.ebay.com/aw/announce.shtml
Ebay will likely update that thread to indicate the issue has been resolved once they have a solution in place but I will continue to monitor the situation and post further updates to this thread as additional information becomes available as well.
-Mike