User made an expense entry that needs to be directed to a liability account in the Chart of Accounts. When trying to select the expense account, the following message is displayed:
'The properties were not updated as the expense entry is already paid'.
It seems that the expense has already been paid via a vendor bill. You need to delete the bill payment to which this expense entry is attached, select the correct account there, and then pay the bill again. You might also need to delete the invoice associated with the expense, if there is any invoice attached to it.