12 Technical SEO Errors That Kill Your Rankings (and How to Find Them in 5 Minutes)
Your site is stuck, and you don’t understand why. You’re publishing content, you have backlinks, the design looks fine - but organic traffic isn’t growing. Often the problem isn’t the content or the competition. It’s small technical issues that search engines see, but you don’t.
These errors don’t announce themselves. The site opens, pages work, everything looks normal. But Google’s crawler trips over them every time it visits, and quietly pushes you down in the rankings. And almost all of them can be found in a couple of minutes and fixed even faster.
Below are 12 errors we regularly catch in SEO audits. For each one: what it is, what damage it causes, and how to check for it yourself.
Security and Basic Markup
1. No HTTPS or Mixed Content
What it is. The site runs on http instead of https, or some resources (images, scripts, styles) load over http on a secure page - that’s mixed content.
What damage it causes. The browser shows “Not secure” next to the address, visitors get scared and leave. Google directly demotes such pages.
How to find it. Open the site and check the lock icon to the left of the address. If there’s no lock or there’s a warning - there’s a problem. Mixed content is visible in the browser console (F12 - Console tab, look for Mixed Content).
2. No Title Tag or It’s Too Short
What it is. The page has an empty or too short title (fewer than 20 characters). The title is that blue line you see in search results.
What damage it causes. Google has nothing to display in the results, so it substitutes whatever it finds - the domain name or a random chunk of text. Clicks will be low.
How to find it. Open the page, press F12, find the <title> tag in the code. Or simply Google your page and see what’s shown in the result title.
3. No H1 or Multiple H1s
What it is. The page has no main H1 heading, or there are two or three of them. H1 is the top-level heading - there should be exactly one.
What damage it causes. The search engine doesn’t understand what the page is primarily about. When there are multiple H1s, the signal gets diluted and the topic reads worse.
How to find it. F12 - search the code for <h1. You should find exactly one. Zero or more than one is worth fixing.
4. No Meta Description
What it is. The page has no short description for the search results - that gray text under the title in the results.
What damage it causes. Google will cut a random snippet from the page, often awkward and cut off mid-sentence. CTR drops because the description doesn’t hook anyone.
How to find it. F12 - search for name="description". If the tag is missing or empty - it needs to be added. Length: 120-160 characters, to the point.
Links, Indexing, and Redirects
5. Broken Links
What it is. Links that lead to non-existent pages and return a 404 or 500 error. They can be internal (to your own pages) or external.
What damage it causes. The crawler wastes crawl budget on dead ends instead of live pages. Users hit an error and get frustrated.
How to find it. Search Console shows crawl errors. For a one-off check, any link crawler tool works - enter your domain and get a list of 404s.
6. No sitemap.xml
What it is. The site has no sitemap, or it’s not specified. A sitemap is a file listing all your pages that you provide to the search engine.
What damage it causes. Some pages may simply not be found by the crawler, especially on large or poorly linked sites. They won’t make it into the index - which means they won’t appear in search.
How to find it. Open yoursite.com/sitemap.xml. If you get a 404 - there’s no sitemap. Check whether it’s been submitted in Search Console.
7. robots.txt Blocking Too Much
What it is. The robots.txt file controls what the crawler is allowed to visit. One Disallow line in the wrong place and an important section is blocked from indexation. There’s also a common conflict: a page is in the sitemap but blocked in robots.
What damage it causes. Blocked pages drop out of search entirely. An accidental Disallow: / removes the entire site from search - and this happens more often than you’d think.
How to find it. Open yoursite.com/robots.txt and read it manually. Check every Disallow line - is it really supposed to be blocked?
8. Redirect Chains and Loops
What it is. Instead of a direct jump, the address routes through several forwarding steps: A - B - C. Or it loops back: A - B - A.
What damage it causes. Each step loses some link equity, and crawling slows down. A loop prevents the page from opening at all - for either the crawler or a human.
How to find it. Any redirect checker will show the full chain for a given URL. The ideal is one hop: http - https or old address - new address, with no intermediate steps.
9. Soft 404
What it is. A non-existent page returns a “200 OK” status code instead of an honest 404. For humans it’s a “nothing found” page, but for the crawler it looks like a working page.
What damage it causes. The search engine indexes empty shells, and junk pages pollute the index. Real pages get less crawler attention as a result.
How to find it. Open a deliberately non-existent URL, e.g. yoursite.com/asdfgh123. Check the response code - it should be 404, not 200. In Search Console such pages are labeled “Discovered - currently not indexed” or “Soft 404.”
10. No Canonical or a Broken One
What it is. The canonical tag tells the search engine which version of a page is the primary one. It may be missing, or point to the wrong place: an http version, a noindex page, or form a chain.
What damage it causes. Duplicate versions of a page compete with each other for rankings instead of combining their weight into one. Google decides which to show - and often picks the wrong one.
How to find it. F12 - search for rel="canonical". Verify that the address inside is the correct https version of the page, with no redirects and no noindex.
Images and Speed
11. Images Without Alt Text and Too Heavy
What it is. Images have no alt attribute (text description), files weigh several megabytes, they’re in old formats instead of WebP, and they all load at once without lazy loading.
What damage it causes. Screen readers can’t read such an image, the page hangs while loading heavy files, and without alt text Google doesn’t know what’s in the image - so image search traffic passes you by.
How to find it. F12 - check <img> tags, they should have alt and loading="lazy". Check file sizes in the Network tab. PageSpeed Insights will separately highlight uncompressed and non-WebP images.
12. Failed Core Web Vitals
What it is. A group of speed and stability metrics: LCP (how long the main content block takes to load), CLS (how much the layout shifts during loading). If they’re in the red zone - the page is slow or jumps around under your fingers.
What damage it causes. This is an official Google ranking factor, not a recommendation. A slow site loses both rankings and visitors - more than half leave before it finishes loading.
How to find it. PageSpeed Insights shows all Core Web Vitals for any URL - enter the URL, get a score and a list of what’s slowing things down. Real user data is visible in the Search Console report.
How to Find Everything in 5 Minutes
Going through this list manually for every page is slow and easy to miss things. It’s faster to run a free audit at seonerve.com: enter a URL and get a list of found issues with priorities already set, so you know what to fix first.
For targeted checks of individual things, Google’s free tools are handy:
- 🟢 PageSpeed Insights - speed and Core Web Vitals for any URL.
- 🟢 Rich Results Test - check markup and how the page looks to the crawler.
- 🟢 Search Console - crawl and indexing errors, and real speed data from live users.
The logic is simple: the audit gives you the big picture and a priority list, while Google’s tools help you dig into a specific problem.
Where to Start
Open your site in the free seonerve.com audit and see how many of these 12 errors you have. Chances are a few will turn up - that’s normal, they accumulate quietly on every site.
From there, two paths. If the errors are simple - title, alt, description - fix them yourself using the list above, it’s quick. If you’re stuck on redirects, canonical, robots, or Core Web Vitals and don’t want to dig in - reach out to us, we’ll fix it for you and hand back a site that the crawler walks without tripping.