SEO issues and how to fix them
These are the 27 checks IndexZero's site audit runs on every page it crawls. Each has a one-line explanation, and the ones with a guide give the exact rule the crawler applies, so you know what a flag does and does not mean.
The guides also cover why the issue matters, what usually causes it, how to fix it at the template rather than page by page, and a prompt a coding agent can run to do the fix in your repo.
Critical (4)
- Crawler was blockedThe site returned a bot challenge or access denial (e.g. a Cloudflare challenge, 403, or 429) instead of the page. It is reported as blocked, not broken, but it means this page could not be audited, and other crawlers like search engines may face similar friction.
- Server error (5xx)The page returned a 5xx server error. Search engines that repeatedly see server errors will crawl the site less and may drop the page from the index.
- Broken internal linkThis page links to an internal URL that returns an error status (4xx/5xx). Broken links waste crawl budget, leak link equity, and frustrate users — they are among the most common and most damaging technical SEO issues.
- Missing title tagThe page has no <title>. The title is the strongest on-page relevance signal and the headline shown in search results; without it search engines generate one themselves, usually badly.
Warning (14)
- Page returns an error (4xx)This crawled URL returned a client error (e.g. 404). If it is referenced from your sitemap or other pages, crawlers keep wasting requests on it.
- Duplicate titleMultiple pages share the same title tag. Search engines use titles to differentiate pages; duplicates make pages compete with each other and depress click-through rates.Duplicate titles: read the guide
- Duplicate meta descriptionMultiple pages share the same meta description, so search results show identical snippets and users cannot tell the pages apart.
- Duplicate page contentTwo or more URLs serve byte-identical visible text. Search engines pick one version to index and ignore the rest, and ranking signals get split across the duplicates.
- Missing meta descriptionThe page has no meta description. Search engines will assemble a snippet from page text, which is often less compelling and hurts click-through rate.Missing meta description: read the guide
- Missing H1 headingThe page has no H1. The H1 tells users and search engines what the page is about; pages without one tend to have weaker topical clarity.Missing H1: read the guide
- Multiple H1 headingsThe page has more than one H1, which dilutes the main-topic signal and usually indicates a templating mistake (e.g. a logo and a headline both marked up as H1).Multiple H1s: read the guide
- Redirect chainReaching the final page requires two or more consecutive redirects. Each hop adds latency, leaks link equity, and burns crawl budget; long chains may not be followed at all.Redirect chains: read the guide
- Redirect loopThis redirect eventually points back to itself, so the URL never resolves. Browsers and crawlers give up with an error.
- Conflicting canonical signalsThe page declares different canonical URLs in its HTML <link rel=canonical> and its HTTP Link header. When signals conflict, search engines ignore both and choose their own canonical.
- Thin contentThe page has very little visible text. Thin pages rarely rank, can drag down sitewide quality assessments, and (if the site renders client-side) may indicate content invisible to plain-HTML crawlers.Thin content: read the guide
- Images missing alt textOne or more images on the page lack alt attributes. Alt text is an accessibility requirement and the main way search engines understand images.Missing alt text: read the guide
- Orphan pageNo crawled page links to this URL — it was only discoverable via the sitemap. Pages without internal links receive little crawl attention and no internal link equity, and users can't find them by browsing.Orphan pages: read the guide
- Page has no outgoing linksThe page contains no links at all — a dead end. Link equity that flows into it stops there, crawlers have nowhere to go next, and users have to reach for the back button.
Info (9)
- Title too longThe title exceeds ~60 characters, so search results will truncate it and the ending may be cut off mid-phrase.
- Title too shortThe title is under ~10 characters, which is usually too generic to describe the page or attract clicks.
- Meta description too longThe meta description exceeds ~160 characters, so search engines will truncate the snippet.
- Meta description too shortThe meta description is under ~70 characters. Short descriptions waste the snippet space search results give you, and search engines often ignore them in favor of text pulled from the page.
- Heading levels skipThe heading hierarchy skips levels (e.g. an H4 directly after an H2). This weakens document structure for accessibility tools and content parsing.
- Slow server responseThe HTML response took over 1.5 seconds. Slow time-to-first-byte drags down every downstream performance metric and reduces crawl rate on large sites.
- Page is noindexThe page asks search engines not to index it (via robots meta tag or X-Robots-Tag header). That's often intentional — this is a heads-up, not an error.
- Canonicalized to another URLThe page declares a different URL as its canonical, telling search engines to index that URL instead. Fine when intentional (parameter pages, syndication) — a problem if this page was meant to rank.
- Page is deep in the site structureThe page is 5+ clicks from the homepage. Deep pages get crawled less often and receive less link equity.