How To Fix IW406 - Order type & requires external number; see message long text

SAP Error Message - Details

• Message type: E = Error

• Message class: IW - Order Processing

• Message number: 406

• Message text: Order type & requires external number; see message long text

What causes this issue?

You cancelled the entry of an external number for the
<GL:order_type>order type</> &V1&. However, you must assign an external
number for a <GL:maintenance_order>maintenance order</> of this order
type.

System Response

INCLUDE 'VERARBEITUNG-ENTER' OBJECT DOKU ID TX LANGUAGE E
The window for external <GL:number_assignment>number assignment</> will
appear again, so that you can assign an external number.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

If you want to retain order type &V1&, you must assign an external
number for the maintenance order.
If you do not want to assign an external number for the maintenance
order, you must select an order type which requires internal number
assignment.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message IW406 - Order type & requires external number; see message long text ?

  The SAP error message IW406 indicates that the order type you are trying to create or process requires an external number assignment, but the system is not able to generate or assign a number automatically. This typically occurs in the context of creating maintenance orders, production orders, or other types of orders in SAP.
  
  Cause:
  The error arises when:
  
  The order type is configured to require an external number assignment in the order type settings.
  The user has not provided a number for the order, and the system is unable to generate one automatically due to the configuration settings.
  
  
  Solution:
  To resolve the IW406 error, you can take the following steps:
  
  
  Check Order Type Configuration:
  
  Go to the transaction code OMH1 (for maintenance orders) or CORM1 (for production orders) depending on the type of order you are dealing with.
  Look for the specific order type that is causing the issue.
  Verify the settings for the order type, particularly the "Number