Hello Marco,

Thank you for reaching out and I am happy to help!
I’ve checked your website and as I can see, the W3 Total Cache is active on your website:

<!--
Performance optimized by W3 Total Cache. Learn more: https://www.boldgrid.com/w3-total-cache/

Object Caching 0/0 objects using APC
Page Caching using APC 
Database Caching 17/4983 queries in 13.915 seconds using APC

Served from: stiwl-mur.de @ 2025-05-26 19:54:33 by W3 Total Cache
-->

Can you please share if you are still experiencing issues with the activation and can you please confirm the plugin is activated?
Thanks!