To login with root user instead of ubuntu, centos user in Cloud VPS Plans.

First, log in to the server with the ubuntu user using the password on the panel.

Then type the following command and press enter.

sudo su

Then type the following command and press enter.

sudo visudo or nano /etc/sudoers

Add the following to the bottom line and save.

root ALL=(ALL) NOPASSWD: ALL

Set a password for the root user with the command below.

passwd root