Need to increase response server timeout with firefox ?
Go to about:config and search for the key name network.http.response.timeout and change to the desired value (in seconds).
Do not forget to set it back to its default value (default:300 seconds, a coffee break !)
Thanks to http://morgb.blogspot.fr/2014/05/firefox-29-and-http-response-timeout.html
and mozilla support forum https://support.mozilla.org/en-US/questions/998088