Are you sure?
Since I am not that technical (read unable to solve this), i was thinking to rebuild the site into your JA Mono quickinstall package for Joomla 4. First I updated Joomla to the latest version.
See solj4.0408429181.nl
When I am trying to see the 404 page - it is impossible. I get an 500 error - like I did on solyscreen.0408429181.nl.. Than i turned on error reporting.
If this is a Joomla bug/thing, why can I see the 404 page on agungs.0408429181.nl and not on solyscreen.0408429181.nl or solj4.0408429181.nl
Any tips on how I can solve this.. I could really use some help.