"401 Unauthorzied" for public NPM packages



All of our builds are failing with “401 Unauthorzied” errors from registry.npmjs.org and registry.yarnpkg.com, but I can access these URLs from outside of Circle. Is there a misconfigured proxy cache involved maybe?

error An unexpected error occurred: "https://registry.yarnpkg.com/@segment/loosely-validate-event/-/loosely-validate-event-1.1.2.tgz: Request failed \"401 Unauthorized\"".
info If you think this is a bug, please open a bug report with the information provided in "/usr/src/app/yarn-error.log".
info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
error https://registry.npmjs.org/@types/async/-/async-2.0.49.tgz: Request failed "401 Unauthorized"