files are getting gzipped, but advagg can't detect it

I'm using apache as webserver, but the status report page is full of this message, that the js and css compression fails.
And infact if I analyze my website with page speed insight of Google, it appears that the compression is not active. -But if I deactivate advagg, compression is ok.
For security, I disable httprl because I obtained an error on apache logs, so this is the output of the status page of drupal without httprl:

Avviso
Adv CSS/JS Agg - gzip
Gzip is failing for js files.
The web servers configuration will need to be adjusted. In most cases make sure that the webroots .htaccess file still contains this section "Rules to correctly serve gzip compressed CSS and JS files". Certain default web server configurations (nginx) do not gzip HTTP/1.0 requests. If you are using cloudfront you will have to add metadata to the .gz files. There are some other options if using cloudfront. Raw request info: 
stdClass Object
(
    [request] => GET /sites/default/files/advagg_js/js__3mCpwGbHDkeT0pYyiZrzzNIofEMD4ltVSKIpamKQrwc__2xzFf2g6ElNHsTFWFbMz2jqLTc5B0dKLL9ZPP7vPDNQ__6a_L5oxc4U5ZDH_in2fiFSxqwf81vBvrlCq_y2SS9Ao.js HTTP/1.0
Accept-Encoding: gzip, deflate
Connection: close
Referer: http://www.nvapple.it/admin/reports/status
User-Agent: Drupal (+http://drupal.org/)
Host: www.nvapple.it
    [data] => ...
    [protocol] => HTTP/1.1
    [status_message] => OK
    [headers] => Array
        (
            [server] => Apache/2.2.22 (Ubuntu)
            [vary] => Accept-encoding
            [cache-control] => max-age=31449600, no-transform, public
            [etag] => W/"PSA-L_6_PEKMfc"
            [last-modified] => Wed, 14 Oct 2015 12:30:56 GMT
            [x-content-type-options] => nosniff
            [content-type] => application/javascript
            [content-length] => 19403
            [accept-ranges] => bytes
            [date] => Wed, 14 Oct 2015 12:50:03 GMT
            [x-varnish] => 187751055 187749813
            [age] => 1148
            [via] => 1.1 varnish
            [connection] => close
        )

    [code] => 200
)
OK