How To Fix 5W123 - Prefix number &1 is not in the customer namespace

5W123 - Overview

• Message type: E = Error

• Message class: 5W - Messages for PD (Particularly Workflow)

• Message number: 123

• Message text: Prefix number &1 is not in the customer namespace

What causes this issue?

You have tried to create a prefix number that is not in the customer
namespace.

System Response

The entry cannot be created.

How to fix this error?

Please choose a prefix number between 900 and 999.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.

5W123 - Details

• The SAP error message 5W123 indicates that the prefix number specified (represented by &1) is not recognized as being part of the customer namespace. This typically occurs in the context of SAP development, particularly when dealing with objects like function modules, classes, or other development objects that require a specific naming convention.
  
  Cause:
  
  Incorrect Prefix: The prefix used in the object name does not match the defined customer namespace. In SAP, customer namespaces are usually defined by a specific range of characters (e.g., Z or Y).
  Namespace Configuration: The system may not be configured correctly to recognize the customer namespace, or the prefix may not have been properly registered.
  Development Object Naming: When creating new development objects, the naming convention must adhere to the rules set for the customer namespace.
  
  
  Solution:
  
  Check Prefix: Verify that the prefix you are using is indeed part of the customer namespace. If you are using a prefix that is not