Error pages
- Create custom 404 pages: Google Search Console Help.
- Use a 404 page analyser to check it.
- Use a 301 page to redirect users to a new page or website when the old URL is not working anymore check out this useful article from ahrefs.
- Create custom 401 pages if you have sites which require admin rights.
- Users should never be confused about what happened and where to go next.
Best practice
- Make sure your 404 page is unique and brings the user back to your homepage (check out our 404 page https://www.renuo.ch/de/404)