Issuer of SSO-Ticket not authorized

Dear all,

I get the message above in my developer traces after testing a system connection via connectors (JCO). I've exported the certificate from my TicketKeystore. The one with -cert at the end and imported it to ABAP backend in strustsso2 and added to acl. I've tried it with to backend systems and I will get the same error. What can be the reason?

Thanks!