I had the same issue and once I created a dummy user manually created some groups (in the dashboard) and assigned users to the groups the issue went away. It may just be a lack of content causing this issue. Another thing that can cause this is a cloud service. If you are using a cloud service like coudfare (which can come in some hosting packages automatically) you need to set it to developers mode. Otherwise it will give you 404 not found errors even on freshly published articles. Good luck with this issue.
