Thank you for the quick reply.
The site has cloudlare enabled for static files. My problem has already been solved. It turned out that the first time the plugin was started, the cache time was set to 7 days and later it was changed to 30 minutes. However, after the change, there were still files on the server with a lifetime of 7 days that were not deleted. After manual removal, the new cache now works correctly.
I still have a question about how preload cache crewler works.
I have the crawler set to renew all caches every 1 hour. I have information in the crawler plugin that has crawled all pages each time. But as far as I can see this crawler just makes a new cache of these pages which do not have any cache. If the site already has a cache done before then it is not replaced. Does it work like this or is it a problem with me?
If this works as described, I have a question whether it is possible to automatically start the crewler every time the cache is cleared or that the crawler will revive the cache for all pages, even for those for which the cache is already created.