How To Fix W_CB411 - No external number assigned (number range &1 &2 is external)

SAP Error Message - Details

• Message type: E = Error

• Message class: W_CB -

• Message number: 411

• Message text: No external number assigned (number range &1 &2 is external)

What causes this issue?

External number assignment is active for this number range. In this case
<(>,<)> you implement the method EXTERNAL_NUMBER_ASSIGNMENT in BAdI
<DS:SIMG.WCB_NUMBER_CHANGE>WCB_NUMBER_CHANGE</> to determine the
external number. This BAdI has been implemented, but the method does not
return a number.

System Response

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?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.