When a corporation receives exceptionally unfavourable news, the stock price drops dramatically. As a result, the stock continues to hit lower circuit restrictions on a regular basis, and no new customers come in to buy these shares. This is most common with penny stocks with little or no liquidity.

When there is a lot of purchasing pressure and demand for a certain stock, there may be a lot of bids but no one wanting to sell.
This is why, even though the order was placed correctly, it may not be executed because it is an open order.

Order matching on the exchange takes place on a price-time priority basis when you place an order during normal market hours. This means that orders are filled in the order they are received (queue system). If other individuals have placed orders before you, yours will only be fulfilled if the orders placed before you are filled.

To go ahead of the line, you can do the following:

1. After 3:45 p.m., place an AMO - Limit/Market order. (Market orders are more likely to be filled.)
2. Place a market or limit order at 9:00 a.m., before the market opens.
An AMO has a lower chance of being executed than a pre-market order. However, placing an AMO is more convenient because you can do so anytime between 3:45 PM and 8:57 AM for NSE and 3:45 PM to 8:59 AM for BSE, rather than waiting for pre-market hours.

Even if you place an AMO or a pre-market order, there is no guarantee that it will be filled. This holds true for all brokers.