Brotli incompatibility?

Hi, since I activated Brotli (Google compression) I have this problem.
"It seems your server setup does not support headers in .htaccess. You should either fix this (install mod_headers) or deactivate the "Enable direct redirection to existing converted images?" option. Otherwise the Vary:Accept header will not be added and this can result in problems for users behind proxy servers (ie used in larger companies)"

And I have add this code on htaccess:

# BROTLI set
<IfModule mod_headers.c>
# BROTLI Static - Precompressed
# Serve brotli compressed CSS and JS files if they exist and the client accepts brotli.
    RewriteCond "%{HTTP:Accept-encoding}" "br"
    RewriteCond "%{REQUEST_FILENAME}\.br" "-s"
    RewriteRule "^(.*)\.(js|css)"              "$1\.$2\.br" [QSA]
# Serve correct content types, and prevent double compression.
    RewriteRule "\.css\.br$" "-" [T=text/css,E=no-brotli:1,E=no-gzip:1]
    RewriteRule "\.js\.br$"  "-" [T=text/javascript,E=no-brotli:1,E=no-gzip:1]
  <FilesMatch "(\.js\.br|\.css\.br)$">
# Serve correct encoding type.
    Header append Content-Encoding br
# Cache Control and Enable CORS
    ExpiresActive On
    ExpiresDefault  "access plus 1 month"
    Header set Cache-Control "public, immutable, max-age=2628000, s-maxage=2628000"
    Header set Access-Control-Allow-Origin "*"
    Header append Vary Accept-Encoding
  </FilesMatch>
</IfModule>

How can I solve it?
Thanks