we are currently trying to configure Single Sign-On using a solution provided by Ping Identity. The respective [logon module|http://documentation.pingidentity.com/display/SAPNW/Introduction] has been integrated into a login stack consisting of the following modules:
1) Evaluate ticket
2) Ping Federate
3) Basic Authentication
4) Create ticket
During the logon process, the logon stack is processed different times as can be seen with the help of SAP's Diagtool: Two times using a Guest user for whom authentication does not succeed and another time with a test user correctly authenticated with Pingu2019s SSO solution. The logon stack does correctly identify the test user as being present in the UME user store and it does also issue a SAP Logon Ticket. However, the overall portal authentication does not succeed as the logon stack finally terminates with an error message:
User is already logged in with user name [Guest] but attempt to re-authenticate with user name [testUser].
Exception : Call logout before login.
It seems as if the logon process does not manage to logoff the Guest user and is thus unable to assign the login context to the test user.
Does anybody know this issue? What could be the reason for this behavior? We tried different configurations of the logon stack, different test users etc. but so far, nothing has helped to solve the problem.
Thanks for your help,