Why CNC orders need Margin

Hai
I tried to place a CNC order for PGINVIT 25 quantity at 95.9 Rs today. It comes to 2397.5 Rs. I had 3300 Rs in my account at that time. However order didn’t go through and the message displayed was Insufficient Margin. I am confused. Do we need Margin even to place CNC orders and that too twice the amount. Please help me understand. Attached the screenshot with error message

Hi @doctrader, you will need amount equivalent to Quantity * Price for buying shares.

Looks like you have received premium from selling options. On the day you sell options, the premium can only be used for buying options, for all other purposes like buying shares, it can only be used from the next day.