Hello @leiderbass

Thank you for your inquiry and I am happy to assist yo0u with this.
Most of the website speed test solutions suggest that you need to have the expires header enabled for static files etc.
Enable the Browser Cache in Performance>General settings and save all settings. Go to Performance Browser Cache and enable toe following in General sub-box:
Set Last-Modified header
Set expires header
Set cache control header
Set entity tag (ETag)
Enable HTTP (gzip) compression
Remove query strings from static resources

This will set the options for all sub-boxes (HTML&XML, JS&CSS, Media and other files)
Save all settings and purge the cache.
Thank you!