Alias /.well-known/acme-challenge /var/www/acme/.well-known/acme-challenge
<Location /.well-known/acme-challenge>
    Require all granted
    <IfModule mod_rewrite.c>
        RewriteEngine off
    </IfModule>
</Location>
<IfModule mod_proxy.c>
    ProxyPass /.well-known/acme-challenge !
</IfModule>