By default, Ubuntu 18.x has disabled the use of password login for the root account, for security reasons. Normal use is a less privileged account plus the use of the ‘sudo’ command in the shell. I’ll assume you have read the many warnings against allowing the use of passwords for the root account. And yes, CentOS allows this by default, so it can’t be THAT bad hey 😉
Step 1: Set a root password
Without setting a root password, you will not have password access with the root account. Set it, even if you thought you alreadyd id.
- Log in to ssh with the less privileged account