Issue: Canonical Mismatch Medium

What this means

The page has a <link rel="canonical"> tag, but the href doesn't match the current URL. This tells search engines that this page is a copy and the "real" version is at the canonical URL. The JSON field is canonical_mismatch.

When this is correct

This is expected when intentionally cross-canonicalizing — for example, a print-friendly version pointing to the standard page, or a syndicated page pointing back to the original.

When this is a bug

• Trailing slash mismatches: /page canonicalizes to /page/ or vice versa.
• Protocol mismatches: HTTP page with HTTPS canonical (or reverse after migration).
• Hardcoded canonical: All pages pointing to the homepage.
• Pagination errors: All paginated pages canonicalize to page 1.

How to fix

1. Ensure the canonical URL exactly matches the page's preferred URL.
2. Use absolute URLs including protocol and domain.
3. Check for trailing slash consistency.