Alf_ticket with SSO

Hi,

I've got a problem further to the implementation of an authentification by SSO on an Alfresco platform.

Up to this implementation, we used a generic user to reach a specific page without needing to authenticate but at the same time to reach the contents of the repository of Alfresco.

I call the URL " api / login.json? U=user*pw=pwd " so as to get back an alf_ticket.

Then I put this alf_ticket to call Alfresco webscripts.

Since the SSO configuration, I can't use my specific page anymore.

I obtain an error "404 Not Found" when I use the alf_ticket:
"NetworkError: 404 Not Found - http://serveur/alfresco/s/slingshot/doclib/treenode/node/alfresco/company/home/path?perms=false&children=false&max=-1&alf_ticket=TICKET_ede04027da6fa8346b05ea7a09387f2938bc09f7"

Is it possible to use a generic user with SSO ?
If not, what would be the best practice to use so as to access to a page without authentication ?

Thanks,

Regards