If attempt to set the secure flag to prevent cookies being sent over plain text connection in SimpleSAMLphp
'session.cookie.secure' => true,
then the error occurs:
[a66d809e0f1359fa7d2bcefc] /index.php/Spezial:PluggableAuthLogin SimpleSAML\Error\CriticalConfigurationError from line 306 of /var/simplesamlphp/lib/SimpleSAML/Session.php: The configuration is invalid: Setting secure cookie on plain HTTP is not allowed.
Backtrace:
#0 /var/simplesamlphp/lib/SimpleSAML/Auth/Simple.php(53): SimpleSAML\Session::getSessionFromRequest()
#1 /var/www/html/extensions/SimpleSAMLphp/includes/SimpleSAMLphp.php(208): SimpleSAML\Auth\Simple->__construct(string)
#2 /var/www/html/extensions/SimpleSAMLphp/includes/SimpleSAMLphp.php(104): SimpleSAMLphp::getSAMLClient()
#3 /var/www/html/extensions/PluggableAuth/includes/PluggableAuthLogin.php(36): SimpleSAMLphp->authenticate(NULL, NULL, NULL, NULL, NULL)
#4 /var/www/html/includes/specialpage/SpecialPage.php(600): PluggableAuthLogin->execute(NULL)
#5 /var/www/html/includes/specialpage/SpecialPageFactory.php(635): SpecialPage->run(NULL)
#6 /var/www/html/includes/MediaWiki.php(307): MediaWiki\SpecialPage\SpecialPageFactory->executePath(Title, RequestContext)
#7 /var/www/html/includes/MediaWiki.php(940): MediaWiki->performRequest()
#8 /var/www/html/includes/MediaWiki.php(543): MediaWiki->main()
#9 /var/www/html/index.php(53): MediaWiki->run()
#10 /var/www/html/index.php(46): wfIndexMain()
#11 {main}