TYPO3 9.5 URL Routing with URL Segment is not work

Question

I am not very experienced in Typo3 so I hope my question/problem would be a quite simple one.

I use a Typo3 9.5.0 LTS instanz on Ubuntu with Apache and MySQL.

Problem is that URLS routing (https://typo3.org/community/teams/typo3-development/initiatives/routing/) is not working.

I created a Site Configuration for relevant Pagetree. Within the pages in Backend the URL segment is visible and changeable. This URL segment is also taken correct by menu entries and by the sitemap.

But I could not access the pages with that path (get 404).

to summarize:

• /index.php?id=[URL Segment] works fine.
• /index.php?id=[ID#] works fine.
• /[URL Segment] does not work. Apache creates 404

I have no routeenhacers in yaml site config active and cleared already the cache.

It would be great if someone has an idea where to dig deeper to solve that issue.

Thanks yES