Solution : https://service.sap.com/sap/support/notes/415105 (SAP Service marketplace login required)
Key words :
system issues error message gb021, delivered sap standard system, order master data fields, order master data, missing solution create, start report rgugbr00, added customer fields, add customer fields, field labeled zzcustomer, generate substitute exp
Related Notes :
| 694697 | Substitution for internal order: Field is not existing |
| 20637 | Inserting Fields in Validations and Substitutions |