If your internet access is through a proxy server, you might need to modify npm install commands that access remote repositories. npm uses a configuration file which can be updated via command line:
npm config set
You can locate your proxy settings from your browser's settings panel. Once you have obtained the proxy settings (server URL, port, username and password); you need to configure your npm configurations as follows.
$ npm config set proxy http://<username>:<password>@<proxy-server-url>:<port> $ npm config set https-proxy http://<username>:<password>@<proxy-server-url>:<port>
username, password, port fields are optional. Once you have set these, your
npm i -g etc. would work properly.
With all that being said, I highly recommend you keep learning!