How To Fix V1426 - The schedule line quantity is already: &1 &2

V1426 - Overview

• Message type: E = Error

• Message class: V1 - Verkaufsbelegbearbeitung

• Message number: 426

• Message text: The schedule line quantity is already: &1 &2

What causes this issue?

You have reduced the target quantity, although schedule lines for the
material already exist.

System Response

The system does not adjust the schedule lines already existing. The
cumulative order quantity of the existing schedule lines remains &V1&
&V2&.

Error message extract from SAP system. Copyright SAP SE.

V1426 - Details

• The SAP error message V1426 ("The schedule line quantity is already: &1 &2") typically occurs in the context of sales and distribution (SD) when there is an issue with the quantity of goods that are being processed in a sales order or delivery. This error indicates that the quantity you are trying to enter for a schedule line exceeds the quantity that has already been confirmed or allocated.
  
  Cause:
  
  Quantity Exceeded: The quantity you are trying to enter for a schedule line is greater than the quantity that has already been confirmed or allocated for that line.
  Delivery Issues: If you are trying to create a delivery or change an existing one, the delivery quantity may already be set, and you cannot exceed that quantity.
  Stock Availability: There may be stock availability issues where the system does not have enough stock to fulfill the requested quantity.
  Order Modifications: If there have been changes to the