When I reboot my server (not nginx, the whole server), Nginx fails to start automatically. After I logged into the server, I can start nginx manually (service nginx start). It works. But if I restart again, I have to manually start Nginx. When checking the error.log for Nginx, I saw this error repeated several times :

```
2012/08/27 09:19:23 [emerg] 1066#0: bind() to [ipv6]:80 failed (99: Cannot assign requested address)

```

How can I fix this? What is this problem? (Im running an Ubuntu 12.04 server)