One of the reference link "VNF Validation Documentation" in pre-onboarding section under User Guides/Design Service is broken. It could be due to reference link path issue in index.rst file.

File path: docs/guides/onap-user/design/pre-onboarding/index.rst

We can fix that issue by replacing with the below

.. toctree::
 :maxdepth: 1
 :titlesonly:

../../../onap-provider/vnfvalidator.rst