Issues:what they mean and how to fix
Overview of issue types and recommended fixes.
4xx / 5xx
Broken pages or server errors. Fix the page or set up a 301 redirect to the correct URL.
Canonical (external / missing / conflict)
Add a self-referencing canonical tag;resolve conflicts so the canonical points to the correct URL.
Missing or duplicate title / meta
Use unique titles (50–60 chars) and meta descriptions (150–160 chars) for each page.
Duplicate content
Differentiate content or use canonical to point to the preferred URL.
Multiple H1 or missing H1
Use one descriptive H1 per page.
Redirect chain / loop
Shorten to a single redirect;remove loops.
Orphan / deep / weak pages
Add internal links;reduce depth so important pages are within a few clicks.
Non-HTTPS,long URLs,missing alt
Redirect HTTP to HTTPS;shorten URLs;add alt text to images.