Hi,
To use SSO you should:
1. Install it by running Plesk CLI installer (/usr/local/psa/admin/bin/autoinstaller) and selecting SSO component.
Or you can download and install required packages manualy. Packages can be downloaded here:
http://autoinstall.plesk.com/SSO_2.1
2. Make sure that SSO server is running:
/usr/local/etc/rc.d/sw-cp-server status
or
/etc/init.d/sw-cp-server status
start it if it is stopped:
/usr/local/etc/rc.d/sw-cp-server start
or
/etc/init.d/sw-cp-server start
3. Configure and enable SSO server for Plesk:
/usr/local/psa/bin/sso --set-prefs -server
https://IP_ADDRES_OF_YOUR_SERVER:11443
/usr/local/psa/bin/sso --enable
4. Enable SSO for Sitebuilder:
/usr/local/sitebuilder/utils/sso_config --enable_sso --server_url=https://IP_ADDRESS_OF_YOUR_SERVER:11443/
5. Configure global accounts:
http://download1.swsoft.com/Plesk/Plesk8.6/Doc/en-US/plesk-8.6-unix-administrators-guide/53086.htm
In case of any issues you should check what records appear in the following logs files:
/var/log/sso/sso.log
/usr/local/sitebuilder/tmp/sso_config.log