If your server time isn't correct follow these steps to synchronize it:

Log in to your server from shell and stop ntp daemon:

 killall -9 ntpd

Define new ntp server:

 ntpdate pool.ntp.org

Start ntp daemon:

 /usr/sbin/ntpd

Check if your server time and date are correct:

 date
                                                                                                                                                                                                                                                    
 Wed Aug 22 11:08:13 CEST 2012