Solution : https://service.sap.com/sap/support/notes/886571 (SAP Service marketplace login required)
Key words :
illegal languages, illegal language, unicode client, client calls, unicode server, developer trace, trace message
Related Notes :
1319517 | Unicode Collection Note |
881781 | Unicode/non-Unicode RFC language and code page assignment |
814707 | Troubleshooting for RFC connections Unicode/non-Unicode |
663089 | RFC bit options in transaction SM59 |