Stop-loss order for this stock is allowed in normal session only
For example, during the normal trading session (9:30 a.m. ET - 4 p.m. ET), you could place a limit order to sell ABC Company stock for $20 per share. It is possible that thousands of traders may be interested in purchasing your shares at $20. In the extended-hours trading session, however, your same sell order for ABC Company stock at $20 BSE Trading Rules - Bombay Stock Exchange