# SAML > SAML authentication plugin for XO-Server This plugin allows SAML users to authenticate to Xen-Orchestra. The first time a user signs in, XO will create a new XO user with the same identifier. ## Configuration In the "Settings" then "Plugins" view, expand the SAML plugin configuration. Then provide the needed fields: ![](samlconfig.png) Save the configuration and then activate the plugin (button on top). > Important: When registering your instance to your identity provider, > you must configure its callback URL to > `http://xo.example.net/signin/saml/callback`! ## Debugging If you can't log in with your SAML settings, please check the logs of `xo-server` while you attempt to connect. It will give you hints about the error encountered. You can do that with a `tail -f /var/log/syslog -n 100` on your XOA. ## Missing plugin? If you don't find the SAML plugin in the list, be sure to have it displayed in your Xen Orchestra configuration (in `/etc/xo-server/config.yaml`): ``` plugins: auth-saml: ```