10 Technical SEO Issues That Are Killing Your Rankings (And How to Fix Them)

You can have the best content in your industry and still rank poorly if your website's technical foundation is broken. Technical SEO is the invisible scaffolding that determines whether Google can find, understand, and rank your pages. When it fails, everything else fails with it.

Here are the 10 most common technical SEO issues we see — and exactly how to fix each one.

1. Slow Page Speed and Failing Core Web Vitals

Why it matters: Google uses Core Web Vitals (CWV) as a ranking factor. Pages that load slowly lose visitors before they even see your content. In 2026, the three metrics that matter are Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS).

Common causes: Unoptimised images, excessive JavaScript, render-blocking CSS, slow server response time, no CDN.

How to fix it:

• Compress images to WebP or AVIF format
• Lazy-load images below the fold
• Minify and defer non-critical CSS and JavaScript
• Use a CDN (Cloudflare's free tier is a solid start)
• Aim for LCP under 2.5 seconds, INP under 200ms, CLS under 0.1

2. Missing or Misconfigured Robots.txt

Why it matters: Your robots.txt file tells search engines what they can and can't crawl. A single misplaced directive can block your entire site from being indexed.

Common causes: Leftover Disallow: / from a staging environment. Blocking CSS or JS files that Google needs to render your pages. Missing the file entirely.

How to fix it:

• Check your robots.txt at yourdomain.com/robots.txt
• Ensure it's not blocking important pages or directories
• Include your sitemap URL: Sitemap: https://yourdomain.com/sitemap.xml
• Use Google Search Console's robots.txt tester to validate

3. Broken Internal Links and 404 Errors

Why it matters: Broken links waste crawl budget, create a poor user experience, and leak link equity. If Google encounters too many 404s, it may reduce how frequently it crawls your site.

Common causes: Deleted pages without redirects. URL structure changes. Typos in links. Products or services removed.

How to fix it:

• Run a site crawl to identify all broken links
• Set up 301 redirects for deleted pages that had traffic or backlinks
• Update internal links to point to the correct URLs
• Create a custom 404 page that helps users find what they need

4. Missing or Duplicate Title Tags and Meta Descriptions

Why it matters: Title tags are one of the strongest on-page ranking signals. Missing titles mean Google has to guess what your page is about. Duplicate titles confuse Google about which page to rank for a given query.

Common causes: CMS templates generating identical titles. Pagination pages without unique titles. New pages published without SEO review.

How to fix it:

• Every page needs a unique title tag (under 60 characters) and meta description (under 155 characters)
• Include target keywords naturally in the title
• Use your CMS's SEO plugin (Yoast, Rank Math, etc.) to audit across the site
• For paginated pages, use "Page 2 of [Topic]" patterns

5. No SSL Certificate (or Mixed Content)

Why it matters: HTTPS has been a ranking signal since 2014. Beyond rankings, browsers now display prominent warnings for non-HTTPS sites, destroying trust instantly.

Common causes: Never migrated to HTTPS. Mixed content — the page loads over HTTPS but embeds images, scripts, or iframes over HTTP.

How to fix it:

• Install an SSL certificate (free through Let's Encrypt or your hosting provider)
• Set up 301 redirects from all HTTP URLs to HTTPS
• Scan for mixed content and update all internal resource URLs to HTTPS
• Update your canonical URLs and sitemap to use HTTPS

6. Poor Mobile Usability

Why it matters: Google uses mobile-first indexing — it crawls and ranks your mobile site version, not desktop. If your mobile experience is broken, your rankings suffer regardless of how good your desktop site looks.

Common causes: Non-responsive design. Text too small to read on mobile. Tap targets (buttons, links) too close together. Horizontal scrolling required. Intrusive interstitials (pop-ups).

How to fix it:

• Use responsive design that adapts to all screen sizes
• Test with Google's Mobile-Friendly Test tool
• Ensure body text is at least 16px on mobile
• Space tap targets at least 48px apart
• Avoid pop-ups that cover the main content on mobile

7. Missing XML Sitemap (or a Broken One)

Why it matters: An XML sitemap tells Google which pages exist on your site and how important they are. Without one, Google relies entirely on crawling to discover your pages — which means some may never get found.

Common causes: Never created a sitemap. Sitemap includes noindexed or redirected URLs. Sitemap exceeds 50MB or 50,000 URLs without being split. Sitemap URL not submitted to Google Search Console.

How to fix it:

• Generate a sitemap using your CMS or a tool like XML-Sitemaps.com
• Include only indexable, canonical URLs (status 200)
• Submit it to Google Search Console and reference it in robots.txt
• Update it automatically when you add or remove pages

8. Redirect Chains and Loops

Why it matters: A redirect chain occurs when URL A redirects to URL B, which redirects to URL C. Each hop wastes crawl budget and dilutes link equity. Redirect loops (A → B → A) make pages completely inaccessible.

Common causes: Multiple site migrations without cleaning up old redirects. HTTP → HTTPS redirect stacking with www → non-www redirect. CMS plugins creating conflicting redirects.

How to fix it:

• Audit all redirects and shorten chains to single hops (A → C directly)
• Fix any loops immediately — they make pages unreachable
• After a site migration, audit redirects within 30 days
• Use server-level redirects (in .htaccess or nginx config) instead of plugin-based ones when possible

9. Duplicate Content Issues

Why it matters: When Google finds multiple pages with identical or near-identical content, it has to choose which one to rank. It often chooses wrong — or splits ranking signals between them, weakening both.

Common causes: www and non-www versions both accessible. HTTP and HTTPS versions both indexed. URL parameters creating duplicate URLs (e.g., ?sort=price). Printer-friendly page versions. Boilerplate content across many pages.

How to fix it:

• Set canonical tags on every page pointing to the preferred URL
• Consolidate www/non-www and HTTP/HTTPS with 301 redirects
• Use rel="canonical" for URL parameter variations
• Noindex or canonicalise printer-friendly and filtered pages

10. Missing Structured Data (Schema Markup)

Why it matters: Structured data helps Google understand your content beyond just the text. It powers rich results — star ratings, FAQ dropdowns, product prices, and event listings directly in search results. Pages with rich results get significantly higher click-through rates.

Common causes: Never implemented. Implemented but with errors that prevent Google from using it. Using outdated schema types.

How to fix it:

• Add relevant schema markup: LocalBusiness for service businesses, Product for e-commerce, Article for blog posts, FAQ for FAQ pages
• Use Google's Rich Results Test to validate your markup
• Implement via JSON-LD (Google's preferred format) rather than microdata
• Monitor the Enhancements section in Google Search Console for errors

How to Prioritise These Fixes

Don't try to fix everything at once. Prioritise based on impact:

1. Critical (fix this week): Robots.txt blocking pages, SSL issues, redirect loops, pages returning 500 errors
2. High priority (fix this month): Slow page speed, broken links, missing sitemaps, duplicate content
3. Important (fix this quarter): Missing meta tags, mobile usability issues, redirect chains, structured data

Technical SEO isn't glamorous, but it's the difference between a site that can rank and one that never will — regardless of content quality.

The challenge for most small businesses is knowing these issues exist in the first place. That's where regular automated audits make the difference — they surface these problems every month so you can fix them before they compound.