As a rule, avoid using npm 1.x for the installation because it is not suitable for the process. To upgrade to version 2, run the command below:
root@iZk1ab7zg8omuutv9jwtbyZ:~# sudo npm install -gnpm@2.x
sudo: unable to resolve host iZk1ab7zg8omuutv9jwtbyZ
npm WARN enoent ENOENT: no such file or directory, open '/root/package.json'
npm WARN root No description
npm WARN root No repository field.
npm WARN root No README data
npm WARN root No license field.
The document you have linked to was written in August 2019, it is now very out of date.
Ubuntu 16.04 went end of life in April 2021 (Ubuntu release cycle | Ubuntu) , you REALLY should not be deploying anything new on it.
If you really can't change it to something newer, then you need to look at the https://nodejs.org website for instructions on how to install something MUCH newer than v4.x
Thank you for your suggestion, the first think I will try to update nodejs with new version, if still not solved, will reset image OS system with Ubuntu 20.04.