The config.php file is SimpleSAMLPHP main config file. Use a text editor that supports unix style EOL (not Windows Notepad) to edit this file or edit on your deployed server.
The baseurlpath variable value should be the fully qualified domain name and path to the SimpleSAML public URL. Also make sure to use HTTPS.
The certdata variable defines where in the filessystem the certificates can be found. If this is unset or commented out, please set it. It set to 'cert/'.
This variable needs to the set per an installation. Make sure to follow the directions above this variable in the config.php.
This variable set the domain scope of the SAML session cookie. By default it is set to null, which will limit its scope to just this host. If you behind a load balanacer, make sure to set it to the external name.
The session.cookie.secure variable defines if the cookie can be read only in HTTPS connection. This should be set to TRUE.