ECC/CRM integration in CPI/HCI -> Problem with SOAP Class - IDOCs

Hello Experts,

refering to https://archive.sap.com/discussions/thread/3794183 and https://answers.sap.com/questions/449869/sap-ecc-idoc-errorproblem-with-soap-class-while-se.html, I also received the same error message:

Can you maybe give me information how it is possible to solve this issue?

BR Christof