https://userapps.support.sap.com/sap/support/knowledge/en/3456180
3456180 - Error 'Class II_CRMS4_PRVC_CHANGEPROC_IN is not a proxy class' occurs when making changes...
Error ' Class II_CRMS4_PRVC_CHANGEPROC_IN is not a proxy class ' occurs when making changes for Subscription Contract through the proxy service.