This may happen if you place an at a price outside the Trade Range (TER). The TER is a price range within which a trade can be and is defined by the Exchange. This is done to manage volatility.

The Trade Execution Range is defined as follows:

1. Trades will occur and will be matched only if the trade price is within the Trade Execution Range (TER) based on the contract’s reference price.
2. The reference price for each contract is determined as follows:
   2.1. At Market Open: The reference price is the theoretical price derived from the underlying price (using implied volatility for options contracts and the rate of interest, which is updated daily with the latest 30-day MIBOR rate). If the underlying price is not available, the base price of the contract is used.
   2.2. During Trading Hours: The reference price is the simple average of trade prices for that contract over the last 1 minute. For contracts traded within the last minute, this reference price is updated continuously on a rolling 1-minute basis.
   2.3.For All Other Contracts: The reference price is the theoretical price based on the most recent available underlying price and is updated regularly throughout the day (every 30 minutes).
3. The Execution Range is the range on both sides of the reference price, as specified below for each segment:
   

4. The existing operating ranges remain unchanged. Orders that fall within the operating range will be accepted as usual.
5. If an order is within the operating range but could lead to a trade outside the execution range, the Exchange will cancel such an order, either partially or in full, as applicable.

The Trade Execution Range does not apply to long-term Option contracts on NIFTY. You can refer to the NSE circular for more information.