Margin required in BO F&O order was shown more than what i checked online

I had a margin of around 19000 in my zerodha account and i wanted to trade in BO, F&O order of Nifty futures. I went on the margin calculater website of zerodha and it showed that i required only 8918/- for buying 1 lot but when i tried to execute the order it showed that i did not have enough margin and in fact said that i needed 891000/-. please help me in this matter. I have also pasted a pic for more clarification. i was using kite mobile.

What was your StopLoss.

If I am not Wrong All BO/CO Orders get Executed After 9:15 AM. Before this all orders will be rejected.

Thank u for the prompt reply. I caught my mistake. I was filling in the wrong stop loss and target.