Rated 1 out of 5 stars

It didn't work at all for me. I installed it, it showed the icon on the action page. I made sure that I was signed in and I set a snipe amount. It never even placed the bid. I would have won the auction had the bid been placed.

This review is for a previous version of the add-on (1.2.4). 

Check the "My Status" field for the exact reason or contact support

Sniping does not guarantee winning. You have to meet eBay's and seller's requirements in order to win.
You can always check the "My Status" field for the exact reason on why your bid was not accepted by eBay.