SAP Message B1533 - The field & has already been assigned to the SAP code

Diagnosis Each field with an SAP code must be assigned to a field with an ISOcode. The ISO code field &v1& cannot be assigned to another SAP code becauseit is already assigned to the SAP code field &v2&. Procedure Choose a different ISO code field. If this is not possible, theexternal structure is incorrect and another ISO code field should beincluded.