How To Fix V1821 - Do not mix schedule lines with and without purchase order types

V1821 - Overview

• Message type: E = Error

• Message class: V1 - Verkaufsbelegbearbeitung

• Message number: 821

• Message text: Do not mix schedule lines with and without purchase order types

What causes this issue?

You have tried to create a schedule line for an item which already has
other schedule lines. These exisiting schedule lines refer to order
type '&V3&'.
The schedule line you just entered has schedule line category '&V1&'.
Order type '&V2&' belongs to this category.
The error message occurred because either order type '&V2&' or '&V3&'
is empty.

How to fix this error?

Change the schedule line categories so that either all or none of the
schedule lines for the item have an order type.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message V1821 - Do not mix schedule lines with and without purchase order types ?

  The SAP error message V1821, which states "Do not mix schedule lines with and without purchase order types," typically occurs in the context of sales order processing and scheduling agreements. This error indicates that there is a conflict between schedule lines that are associated with purchase orders and those that are not.
  
  Cause:
  The error arises when you attempt to process or manage schedule lines in a way that mixes those linked to purchase orders with those that are not. This can happen in various scenarios, such as:
  
  Sales Order Creation: When creating a sales order, if some schedule lines are linked to a purchase order and others are not, SAP will throw this error.
  Delivery Processing: During delivery processing, if you try to deliver items that have different types of schedule lines, the system will not allow it.
  Inconsistent Data: There may be inconsistencies in the data where some items are set up to