401 Unauthorized with npm client versions 5.0.0 to 5.0.3

Problem

If trying to access a Nexus Repository Manager npm repositories with npm client versions 5.0.0 to 5.0.3, the requests will be blocked with 401 Unauthorized responses. If using an earlier version of npm client, authentication works.

Cause

The npm client versions 5.0.0 to 5.0.3 have a regression where the old basic authentication method is not supported. See the following npm bug:

https://github.com/npm/npm/issues/16528

The problem is not caused by any issue with Nexus Repository Manager.

Solution

Below are possible solutions to the above npm issue:

• upgrade to npm version 5.0.4 or greater
• or downgrade to an npm version earlier than 5.0.0
• and/or run npm login and use npm bearer token realm in Nexus 3.x .
• and/or possibly try this client based manual workaround specifying registry specific auth