The error message "Server Response on static files" appears in the reports in the TYPO3 backend, if the server delivers files with multiple extension, e.g. "secret.html.txt" in the wrong MIME type (here as text/html instead of correctly as text/plain). This is a security vulnerability because editors can bypass the upload filter (e.g. no uploading of .html files in the fileadmin directory) in this way.
Add the following entries to your .htaccess file in the root path: