The customer's account balance in the customer's tab is less than the outstanding on account sales in the Sales History.
- Retail POS for Mac or PC
This is caused by an overpayment on one of the previous on account sales.
The sale will show up as Account Sale (instead of Account sale, paid). Removing the excess payment on the sale and issuing the customer a store credit for that amount will resolve the issue.
The customer can then use the store credit toward their next sale.