Hi,
One of the users provided a lot of useful content to our knowledge base and few days ago for unknown to me reason all of the users including it's author (i still can see it with admin account) lost access to that. Version is quite old, it's 4.3.5 and when i try to see one of the articles i receive this message like in screenshot below:

As i relog as admin i can see full mainpage with roadmaps and content lists to see everything written and also history of last changes. Does anyone know if i can check anything besides group access and page restriction settings because everything on that field was correctly set up, working and being used everyday and nothing was being changed yet issue occured. Thanks a lot for any advice or questions!