Add troubleshooting scenario for 500 error

doc/user/packages/npm_registry/index.md

@@ -465,3 +465,26 @@ If you get this error, your package name may not meet the
 
 Ensure the name meets the convention exactly, including the case.
 Then try to publish again.
+
+### `npm publish` returns `npm ERR! 500 Internal Server Error - PUT`
+
+This is a [known issue](https://gitlab.com/gitlab-org/gitlab/-/issues/238950) in GitLab
+13.3.x and later. The error in the logs will appear as:
+
+```plaintext
+>NoMethodError - undefined method `preferred_language' for #<Rack::Response
+```
+
+This might be accompanied by another error:
+
+```plaintext
+>Errno::EACCES","exception.message":"Permission denied
+```
+
+This is usually a permissions issue with either:
+
+- `'packages_storage_path'` default `/var/opt/gitlab/gitlab-rails/shared/packages/`.
+- The remote bucket if [object storage](../../../administration/packages/#using-object-storage)
+  is used.
+
+In the latter case, ensure the bucket exists and the GitLab has write access to it.