Koinly auto-detects errors on transactions that result in negative balances. Ex. if you have 0 BTC in your wallet but add a withdrawal of 10 BTC, you will get a negative balance error that looks like this:
Hovering over the info icon will show you the balances after this transaction. As you can see the balance after adding this txn is negative. In order to fix this you simply create a Deposit of 10 BTC before the withdrawal.
If you have a lot of trades or transactions it might be worth adding one large deposit that covers all the negative amount instead of fixing them one by one.