Solution : https://service.sap.com/sap/support/notes/179841 (SAP Service marketplace login required)
Key words :
online dump - type message_type_x, additional key words cj27, form routine nk_extern, apply hot package 01, attached program corr, project planning board, external network number, external number, planning board, choose cancel
Related Notes :
| 340000 | Creating network w/ external number: MESSAGE_TYPE_X |
| 102676 | Termin.when creating subnetwork and external number |