If you report this error, please also report this tracking number which makes it possible to locate your session in the logs available to the system administrator:
The debug information below may be of interest to the administrator / help desk:
SimpleSAML\Error\CriticalConfigurationError: The configuration is invalid: Setting secure cookie on plain HTTP is not allowed.
'baseurlpath' => 'https://' . $_SERVER['HTTP_HOST'] . '/simplesaml/',