Have you tried restarting Ghost?

sudo service ghost restart

If that doesn't fix it, what's the output of

sudo netstat -plutn

and what error do you get when you try to access Ghost?

Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 454/sshd
tcp 0 0 127.0.0.1:2368 0.0.0.0:* LISTEN 564/node
tcp6 0 0 :::22 :::* LISTEN 454/sshd
root@milkoghost:~#

there's basicaly no response from the web server whatsoever.

I'm deeply mad because after tying again to make a backup of my droplet I crashed again my blog. Mad!

and my attempt to restart nginx failed -
root@milkoghost:~# sudo service nginx restart
Restarting nginx: nginx: [emerg] unknown directive "georgievs.net" in /etc/nginx/conf.d/default.conf:3

the content of my /etc/nginx/conf.d/default.conf are here: http://pastebin.com/4EHKzCne

    georgievs.net ;

That line is invalid -- replace it with the following and then restart nginx:

server_name    georgievs.net ;

Kamal, I resolved the problem. the conf file was with a wrong syntaxis of the default.conf file

:) thanks, done that