If your items have closed after setting the Auction End Date through the auction's general settings, you can still set the items to active again through the Manage tab to continue bidding.

To change the auction item status from closed to active, follow the steps below:

Step 1: Navigate to the Manage tab >> Auction Items >> Closed >> use the quick actions on the right to set items Active. You can also select the pencil icon to edit an item and use the Status dropdown to change the status.