In the stock exchange, stocks are bought or sold on a ‘first come, first serve’ queueing basis. This means that, if there are multiple bidders for the same offer, the bidder who placed their first will get their order on priority.
Hence, a limit order may occasionally not get executed partially or completely even when the stocks are available at your limit price range.
If you need further help with this, tap Go To below, select the order, and tap Contact Support.