Facebook Page Plugin giving "Failed to load resource"

I would like to use the Facebook page plugin, but I can not. After adding this code at the beginning of the body tag

 <div id="fb-root"></div>
<script>(function(d, s, id) {
  var js, fjs = d.getElementsByTagName(s)[0];
  if (d.getElementById(id)) return;
  js = d.createElement(s); js.id = id;
  js.src = "//connect.facebook.net/pt_BR/sdk.js#xfbml=1&version=v2.5";
  fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));</script> 

and this at the end tag "body"

<div class="fb-page" data-href="https://www.facebook.com/l2akhilleus/timeline/" data-small-header="false" data-adapt-container-width="true" data-hide-cover="false" data-show-facepile="true" data-show-posts="true">
<div class="fb-xfbml-parse-ignore"><blockquote cite="https://www.facebook.com/l2akhilleus/timeline/"><a href="https://www.facebook.com/l2akhilleus/timeline/">L2Akhilleus</a></blockquote></div></div>

I refresh the page and it does not load or show anything. I went in to inspect element of the page and it returned me this and I do not know how to proceed:

  

file: //connect.facebook.net/en/sdk.js#xfbml=1& version = v2.5 Failed to load   resource: net :: ERR_FILE_NOT_FOUND

I've been in this link and copied all the code and saved it in a file, I called the code <script type="text/javascript" src="js/sdk.js"></script> and it still does not show the plugin in my page ...