This works: ``` npm login npm install @something/private ``` This does not work: ``` npm login yarn add @something/private ``` This is a bit tricky to reproduce if you don't have a private npm registry (or any private registry) access. The config that `npm login` creates by default is: ``` registry=https://registry.qubit.com/ //registry.qubit.com/:_authToken=token ``` Looks like `npm` sends this token to the registry when installing private packages, but `yarn` doesn't. It's probably closely related to #1666 .