A common setting for npm is the Enable Dependency Rewrite option for virtual repositories. This allows Artifactory to cache GitHub metadata associated with npm packages and locally serve the content. When a remote repository is established as the dependency cache, an _external folder will be created that stores GitHub .tar.gz files:

From time to time, you may find that Artifactory is unable to reach GitHub. If you see such occurrences in your logs, consider disabling Dependency Rewrites to see if this resolves that problem.
From time to time, you may find that Artifactory is unable to reach GitHub. If you see such occurrences in your logs, consider disabling Dependency Rewrites to see if this resolves that problem.