Unable to npm install

[creativeRaspberry]

Hi,

I need to customize your project a bit. while running npm install on your app I get: npm ERR! code E404 npm ERR! 404 Not Found - GET https://registry.npmjs.org/material-theme/-/material-theme-3.0.1.tgz - Not found
npm ERR! 404 npm ERR! 404 'material-theme@https://registry.npmjs.org/material-theme/-/material-theme-3.0.1.tgz' is not in this registry.

could you please give a hint how to proceed?

Thanks!