Feeds Importer and cron not running
Where is the site running? You mention you can download the file in your browser, but I wonder if the network from the site to google is different than the network from your computer to google.

What's in the error log in general? When the page goes blank like that it usually means some kind of severe error happened and that should show up in the Administer -&gt; Reports -&gt; Recent log entries page for the database log. Or it might show in the php or apache error logs. The location of those logs depends on your system.

How are you running cron? Depending on how you run it you might see different errors. If you have drush maybe try running cron via drush cron.