You were trying to place a Buy Cover Order and Stoploss price placed was on the higher side, but should be on the lower side. Thus your buy CO order was rejected. The trigger price in your case for the given set of conditions would be 769 (789 - 20).
Hope this helps.
@alokgaira I have been trying whole day, even now. It is a simple code. Even the sample python code shared by @shrini-viswanath gives the same error.
The same code was working till last week Saturday. It has intermittently worked a few times but mostly (90%) of the time gives this error.
I am sharing the snapshot of it from IDE.
The issue you faced on 6th is something which we need to fix and because of that you where not able to cancel(exit) 2nd leg of CO. The square off charges where reverted on 9th.
On the trading session of 9th, 10th and 11th there was an entry mismatch in our order management system while billing because of which few clients where charged for square off and unfortunately you were one of them. This issue was rectified from our OMS vendor and we adjusted the same in ledger for all those users. We would request you to verify once after checking your ledger.
Note: All simple orders of intraday and delivery needs to be squared off from positions whereas if your are trading CO and OCO then this orders have a dependent leg on a counter side open in order book. So to square off CO and OCO you need to send a cancel request for the open order(leg) of CO or OCO. This request will square the position at the CMP. In short CO and OCO cannot be square off from positions and this activity is carried from order book.