Why is Groww balance negative?

Your Groww balance could be negative because:

You did not have enough balance for a trade, and your order got executed at a higher price due to sudden price movement (happens in case of market orders), or

You did not have enough balance to pay for DP charges (deducted when shares are debited from your Demat account).

To avoid penalties, add funds to your Groww balance when it is negative