First login to the ubuntu server via terminal or console

To gain super user access, enter the following command and re-type the user password.

sudo su –


Type the following command to set the password for the Root user

passwd root

set password for root

This will prompt user to enter the new password.
and confirm password

The terminal will return with Password updated successfully!

Simply adding a password for root is not enough for Ubuntu 14.04+ Server.

You need to edit /etc/ssh/sshd_config, and commend out the below line:

PermitRootLogin without-password

Add the following line:

PermitRootLogin yes

permit root login

Then restart SSH:

service ssh restart

restart ssh

Yes you are done…

login using root account