Do your www and bare addresses agree?
It reports the saved result for host canonicalisation.
What Check Engine measures
The check uses the saved test of www redirects. If that test failed, it produces a high finding for a site reachable with and without www, without the expected redirect. It does not choose the preferred host or inspect every internal link. Review the measured host responses before changing server settings.
The check uses the earlier host test. It does not assign a content-duplication percentage or a ranking effect to either host spelling. You choose the preferred address for the business.
How to read the result
The finding is high severity. It describes the observed host setup and does not mean that using www is inherently better or worse than using the bare domain.
Why it matters
A consistent public host gives the site a clear address policy. The useful question is whether the alternate address leads to the intended one, rather than which spelling a tool happens to prefer.
How to fix it
Choose the host your site should use and configure the alternate host to redirect to it. Keep the path and query where appropriate. Align internal links, canonicals and sitemap addresses with that choice. Test both host variants over the relevant schemes after editing server rules, since a working homepage rule may not cover inner paths.
www vs non-www: does it still matter?
What we found in field audits
Problems in Crawlability & indexing were found on 12 of the 14 sites we audited. These are area totals. Read the field-audit method.
Method note
backend/seo_engine/checks/indexability.py, www_canonical, revision 0bb8e8d3.
Common questions
Does the www check choose which host spelling I should use?
No. Choosing the preferred host is left to you. The test reads the saved www redirect result.
How serious is a failed www-to-preferred-host setup?
It gets high severity. Inspect the saved host responses to decide which redirect setting needs repair.
Does a www finding mean the bare domain is inherently worse?
No. The bare domain and www can both be valid choices. What matters here is the observed host setup and expected redirect.