trying to install power bi visual tools but getting error code 429

I'm trying to run "npm install -g powerbi-visuals-tools" to install the power bi visual tools but when I do I get the following:

npm ERR! code E429
npm ERR! 429 Too Many Requests - GET https://registry.npmjs.org/string-argv/-/string-argv-0.1.2.tgz

I don't understand how or why I'm getting this, does anyone know how to resolve?