How to reconcile for historical AP Payments?

The payable Option that accounts for payments 'when payment clears' was turned on on January 1st, 2016.

I would like to start using the cash management module and reconcile for several bank accounts that have "old" payments.

When those payments were created, no clearing account was taking part in the accounting process.

When I try to create a bank statement opening balance statement and reconcile it against all historical "old" payments, the payments get "partially accounted" and the create accounting process in AP fails with the following error:

The account on the gain or loss line is invalid. If you have a gain/loss journal line type defined, please verify the account derivation rule