Common Technical SEO Problems (And How to Spot Them)
The issues we find over and over on real sites - accidental noindex tags, duplicate URLs, redirect chains, JavaScript rendering gaps - and how to check for each one yourself.
Technical SEO problems tend to be binary. Either the site has them or it does not, and when it does, everything else you invest in underperforms.
These are the ones we find most often, roughly in order of how much damage they do relative to how easily they hide. Each has a check you can run yourself.
1. An accidental noindex tag
The most damaging and one of the easiest to miss. A noindex directive tells search engines not to store the page at all.
It usually arrives from a staging environment. The development site is blocked from indexing - correctly - and the setting survives the move to production. Everything looks normal. The pages simply never appear.
How to check: view the page source and search for noindex. Or check Search Console’s Pages report for URLs excluded by ‘noindex’ tag. Do this immediately after any launch or migration.
2. The same content at multiple URLs
A single page reachable at several addresses splits its signals across all of them.
Classic sources: http and https both resolving; www and non-www both resolving; trailing slash and no trailing slash serving the same content; URL parameters from filters, sorting or tracking creating endless variants.
How to check: try loading your homepage as http://, https://, with and without www, and with and without a trailing slash. Every variant should redirect to one canonical version. Then check that self-referencing canonical tags are present.
3. Content that only exists after JavaScript runs
Search engines execute JavaScript, but it happens on a second pass and it is not guaranteed to complete.
If your content is assembled in the browser, you have a dependency you do not need. When it fails, you get indexed pages that appear nearly empty.
How to check: disable JavaScript in your browser and load a key page. Or view source - not the inspector, which shows the rendered DOM, but the raw source. If your main content is not in there, this applies to you.
This is the reason we default to server-rendered HTML on every build. More in website development.
4. Redirect chains and loops
A redirect passes authority, but each hop loses a little and costs crawl budget. Chains build up over years of migrations: URL A redirects to B, which redirects to C, which redirects to D.
Occasionally two redirects point at each other and the page becomes unreachable.
How to check: crawl the site and look for redirect chains. Fix by pointing every old URL directly at the final destination. Also check that internal links point at final URLs rather than through redirects.
5. Orphan pages
Pages with no internal links pointing at them. They may be indexed, but they are disconnected from the site’s structure and receive no internal authority.
How to check: crawl the site to get discovered URLs, then compare against your sitemap or CMS export. Anything in the second list and not the first is orphaned. See how internal linking helps SEO.
6. Sitemaps full of junk
An XML sitemap should list exactly the canonical, indexable URLs you want in the index. Many contain redirects, 404s, noindex pages and non-canonical variants - which sends contradictory signals.
How to check: open your sitemap and spot-check twenty URLs. Do they all return 200? Are they all canonical? Are any of them noindex?
7. Pages competing with each other
Keyword cannibalisation: several pages targeting the same intent, so search engines have to choose between them and often split signals across all.
How to check: in Search Console, look at a query and see which pages rank for it. If the URL fluctuates between two or three of your own pages, you have found it. The fix is consolidation - pick the page that should own the topic, merge the rest into it, and redirect.
8. Missing or duplicated titles and descriptions
Templated titles like “Home | Company Name” across many pages, or descriptions auto-generated from the first sentence of body content.
How to check: Search Console flags duplicates, or a crawler will list them. Every page needs a title that describes that specific page.
9. Broken heading structure
Multiple H1s, headings chosen for visual size rather than hierarchy, or an H4 directly following an H2. This makes the document harder to parse for both search engines and screen readers.
How to check: use a browser extension that shows the heading outline. It should read like a sensible table of contents.
10. Slow interior templates
Performance testing usually happens on the homepage - which is usually the most optimised page on the site. Meanwhile most organic traffic lands on article or product templates that nobody tested.
How to check: run Core Web Vitals on each distinct template, not just the homepage. Prefer field data over lab data where they disagree. Covered in why website speed matters.
11. Blocked resources in robots.txt
Blocking CSS or JavaScript directories prevents search engines from rendering the page as a user sees it, which can affect how mobile-friendliness and layout are assessed.
How to check: review robots.txt for Disallow rules covering asset directories.
12. Structured data that does not match the page
Marking up content that is not visible, or FAQ markup on a page with no FAQs. This is a guideline violation and can lead to rich result eligibility being withdrawn.
How to check: run key pages through a structured data validator, and confirm the marked-up content actually appears on the page.
A one-hour audit
If you only have an hour, do this:
- Check Search Console’s Pages report for unexpected exclusions
- View source on three key pages - confirm content is in the HTML, check for stray
noindex - Test URL variants (http/https, www/non-www, trailing slash)
- Open your sitemap and spot-check twenty URLs
- Run Core Web Vitals on your three main templates
- Check the heading outline on a key page
That will surface most serious problems. It will not find everything - orphans, chains and cannibalisation need a full crawl - but it will tell you quickly whether something structural is suppressing your results.
A full technical audit is where most of our SEO engagements begin, and it ends in a prioritised list rather than a PDF of warnings. Send us your URL if you want to know what is actually wrong.