How does "Auction" work?

How does “Auction” work? I tried to sell in auction after 4 PM but it is giving me below error. What is the time for auction?

Error: Markets are closed right now. Use GTT for placing long standing orders instead.

The Auction markets are open from 2 PM to 2:30 PM. Please check this support article for more details: How to participate in the auction markets on Kite?

thanks. Why is it still showing stocks in Auctions if the timing is only till 2.30 PM?