Flush the caches does not work Elgg 2.3.16

Even though I click "Flush the caches" and get "The site's caches have been flushed" I still see all the old cache files on the server and Elgg ignores the changes in the language files. For example:

private/amelggviews_simplecache/1629569040/default/languages/en.js

...... (many js cache files)

private/amelggsystem_cache/en.lang

I also rebooted the server but it did not help.

How to fix the problem?

Thank you very much