Validation Error 311 while trying to tender an On Account credit to a sales order deposit/payment.

On Account and sales orders (layaways, workorders, backorders) are mutually exclusive.

RMS logic does not allow you to charge a deposit to an account since that is equivalent to taking no money down, so the deposit may as well be zero. While a credit on account could work in this circumstance, the amount on account applied to the sales order would need to update two debit/credit accounts in succession. RMS does not currently support this condition.

As a workaround you have two options.

Option 1 -- Refund the credit on account to Cash as a separate transaction first. To do this recall the customer account and press Shift-F4 Payment, tab to OK, and complete the transaction, selecting Cash as the tender type for the refund. Then immediately create/recall a sales order (layaway, workorder, or backorder) and apply that cash amount as a deposit/payment. If necessary press Shift-F9 Details to over-ride the deposit amount to match. This reconciles the GL accounting entries in RMS to reflect the changes.

Option 2 -- Wait for the customer to pick up their order (partial or full) and apply the On Account credit to the order in the Tender Window. Picking up a sales order is treated differently than entering the original order, as the transaction is booked to sales on that day. When the Tender window appears, enter the deposit amount on file as a credit under On Account then move to another tender type to collect the balance due. If the account credit limit is set to zero you can also press + in the On Account tender to apply any outstanding credit. You will receive a warning if the balance due exceeds the credit amount. You can then select an additional tender type to collect the balance.