Solution : https://service.sap.com/sap/support/notes/389075 (SAP Service marketplace login required)
Key words :
network configuration activation type, attached source code corrections, assign field type 'rfcdest', external tax system work, standard source code, encounter problems updating, problems occur separately, function modules rfc_update_taxes_doc, function module rfc_calculate_taxes_doc, 'ttxd-rfcdest' field
Related Notes :
| 706258 | RFYTXDISPLAY/RFYTXUPDATE: Note the second RFC destination |
| 216364 | Blocked queue / No update to external tax system |