I've the same problem described HERE and I can't understand where is the problem

I've checked cURL library / OpenSSL extension for PHP and fsockopen PHP function and they are ok.
I've Joomla 3.4.4, PHP 5.5.29 and JoomSEF 4.6.3.
In my Google Analytics account settings I've checked my username/password for Google and my Google Analytics Web ID and they are correct.
I've only a doubt about Google API key because the url you linked (code.google.com/apis/console/) redirect me here: console.developers.google.com/project
At that link I've enabled "Analytics API" and "PageSpeed Insights API" because I can't see any other related API useful for me. I've created a "browser key" and a "server key" but nothing seem working.

I still got "The data could not be obtained. Please check your Google Analytics account settings" message.
Where am I doing wrong?