We have a quite new Joomla (3.9.2). But our SFPlus is rather old
and give the following Error while requesting an unknown page: (old 404 error):

JException Object ( [level:protected] => 1 [code:protected] => 404 [message:protected] => Beitrag nicht gefunden [info:protected] => [file:protected] => /usr/www/users/xxx/libraries/legacy/error/error.php [line:protected] => 200

The error-page is unusual long (can not post it all)
Any ideas ?

To make it more precise: The messages coming in the page are more like Joomla dump messages throwing all kind of information even the one from configuration.php (including passwords). Not nice.