But when I'm trying to register the app with the users existing in SAP portal but not in SCC then it gives such error.Should all the SAP portal users must be registered in Sybace Control Center as well ?
In typical scenarios, there should be LDAP security also available at SUP/SMP server level so that all windows user can be reachable/registered to sup server.
now, to register with SAP backend users, there should be mapping between LDAP users and backend users. That's how Single sign on plays a role.
Rgrds,
JK