Correct 301 Redirection NGINX Ubuntu 14.04

Hello all, I have a droplet setup with my domain example.com, my webserver is nginx, I have setup my server blocks in order to have my site in example.com and my blog with blog.example.com, everything was working well, I’am using a CNAME for WWW. and another CNAME for BLOG.

I noticed that I have duplicated content at google ayes because I serve the same site in my www domain and my non-www. I have read some tutorials to redirect all my non-www traffic to my www site.

When I made the changes, my surprise was that now my blog is served in example.com and in blog.example.com, I don’t know what im doing wrong,

My configs in sites-available are:

Main Site:

server{
        listen 80;
        listen [::]:80 default_server;

        root /var/www/main/html;
        index index.html index.php index.htm;

        server_name example.com;

        return 301 $scheme://www.example.com$request_uri;

        location / {
                try_files $uri $uri/ = 404;
        }
}

Blog:

server {
    listen 80;
    server_name blog.example.com;
    location / {
        proxy_set_header   X-Real-IP $remote_addr;
        proxy_set_header   Host      $http_host;
        proxy_pass         http://127.0.0.1:2368;
    }
}

Pretty basic configs that worked before the changes, have to say my blog is running under Ghost, I mantain the blog alive with “supervisord” in the past have used “forever” installed vía npm, I don’t think this is the problem but I think every detail helps.

My “main site” right now is only a “.html” file, as you can see in the config, the priority to serve files is “.html”

Thank you in advance to you all!