I am not able to boot into my ubuntu. Grub gives me this message
How do I boot linux?
what have you done before this happens?
It means that GRUB2 detected an error during boot and cannot pass control to the selected kernel because of a grub.cfg error and thus it reverted to rescue mode.
See the troubleshooting section of this guide: Grub2 - Community Help Wiki
OP the link that is above is a good one if you need some additional help post the the output of this command in the terminal.
sudo fdisk -lu
how can he do this if the server can't boot?
From a live cd.
The grub2 link on the reload from a cd section suggests confirming the partitions with a sudo fdisk -l
I like to see if the person is dual boting with an MS that the bootflag is correct as well hence the -lu
Being a new member I was not allowed to post the link that would give us the complete layout, pretty much. 
not work for me, final i reinstalled ubuntu.