In my case it was a DNS problem. Googling I found that this problem is even happening to some hosting providers. All what I had to do was to change the DNS server in /etc/resolv.conf from our networks IP to 8.8.8.8 (the main google DNS server).
I think that maybe it's a DNS server update thing. We are working with our communications chief to figure out what's happening. In the meantime the above solution should do the trik.