title: Typo3 10.4 Clear cache in Backend throws error: "An error occurred while cleaning the cache" - how to debug?
body: <p>Clear cache in BE throws error: &quot;An error occurred while cleaning the cache&quot;.
  I get no error in the logs, neither in Typo3 BE nor on server side - how can I debug this?</p>
  <p>In the maintenance tools I already:</p>
  <ul>
  <li>Flushed TYPO3 and PHP Cache</li>
  <li>Analyzed Database Structure</li>
  <li>Removed Temporary Assets</li>
  <li>Clear Persistent Database Tables</li>
  </ul>
  <p>I deleted manually all files and folders in typo3temp/var/cache/code and typo3temp/var/cache/data. Also updated reference index. Still same error:</p>
  <p><a href="https://i.stack.imgur.com/rXwgV.png" rel="nofollow noreferrer">screenshot of error message when trying to clean cashes via Typo3 BE</a></p>
  <p>Version: Typo3 10.4.20
  PHP Version 7.4.25</p>