There can be a number of reasons why a bid fails or is unsuccessful. The main reasons would be that you have been out bid or you have entered an amount lower than the next required bid. Check the next bid amount on the bid page. You will also be prompted by the system to revisit the bid page if your bid was unsuccessful. Note, bidders with autobids may out bid you should their auto bid limit be higher than your current bid. Also note on auctions with a reserve price, you will not win the auction if the reserve price is not met, the system will inform you of this but will not display the reserve price.
It is important to remember to refresh your page to ensure you are keeping updated on the current bids. Do not rely on being notified via email as this may take some time to reach your mailbox.
There may also be technical reasons why your bid was not accepted, this could be due to your internet connection (speed and access), traffic load on the site, server response time etc. Although we endeavour to make the bidding process as real time as possible, there may be technical or system limitations that affect the placement of a bid timeously.