Solution : https://service.sap.com/sap/support/notes/889443 (SAP Service marketplace login required)
Key words :
sap ag online service system, /3 front end logon reason, rfc destination saposs, /3 front end, system number 01, group logon, destination saposs, saposs connection, technical settings, transaction oss1
Related Notes :
182308 | Incorrect logon data in R/3 destination SAPOSS |