Relevant versions: This information pertains to Artifactory versions 6.X and above
The npm client is used by many application pipelines to pull javascript dependencies for web UI functionality. It has several unique API calls that may cause errors if not properly handled by Artifactory. When troubleshooting these errors, it's best to compare what is supposed to happen when these calls are executed against what your system is currently experiencing. You can eliminate a great deal of noise by simulating each step your client is taking and examining what HTTP error code is sent by Artifactory.
In general, these are the error codes you might encounter and where you should explore for answers/solutions next:
401: Authentication issue, meaning the user did not use the right username / password
403: Authorization issue, meaning the user does not have access to the requested resource
404: Resource not found, check repository for resource
400: Incorrect request, use cURL to get reason phrase
50X: Server problem, examine the artifactory-service.log (7.X) or artifactory.log (6.X)