Avoid the common SEO mistakes. Find out why even small errors can hurt your website's performance and how to steer clear of them effectively. SEO done properly helps increase visibility in search engines and bring in more visitors, but a few missteps are enough for the result to turn against you.
If you also want to succeed with a multilingual website, it is essential to devote enough time to quality translation, localisation and technical optimisation, including correctly set up hreflang tags. That is how you improve your search rankings, extend your reach and offer users pleasant, relevant content in every supported language.
Why SEO mistakes are worth fixing
SEO mistakes can lead to lower search rankings, lost organic traffic and fewer conversions. Users find you less easily and you miss out on valuable opportunities.
- Lower positions in the results: You lose visibility among your competitors.
- Reduced traffic: The website is harder to find and less visited.
- Competitors overtake you: Others with better SEO win more customers.
- A chance to put things right: Spotting errors early can improve your search results.
One of the most common and at the same time most serious mistakes that can undermine your success is the incorrect implementation of hreflang attributes. While other SEO shortcomings may gradually erode your performance, hreflang errors have an immediate impact because they confuse search engines and frustrate users. A poor hreflang implementation can mean the search engine does not understand how to group the pages correctly, which can hurt indexing and rankings.
In the following part of the article we look at the most common SEO mistakes and show how to fix them effectively.
Missing or empty H1 tag
What it means: The H1 is the main heading of the page and states clearly what the page is about. If it is missing or empty, neither search engines nor users know what the main topic of the page is. This reduces relevance and can confuse visitors.
How to fix it:
- Define a clear main topic and keyword for the page.
- Write a unique, descriptive H1 that contains the keyword.
- Place the H1 as high as possible in the HTML body.
- Keep the H1 to 60-70 characters for better readability.
Example of a correct implementation:
Missing or empty meta description tag
What it means: The meta description is the short text shown under the page title in the search results. Although it does not directly affect rankings, it strongly influences whether a user clicks on your link.
How to fix it:
- Write a unique, engaging description for every page (150-160 characters).
- Place the meta description in the <head> section of your HTML page.
- The description should contain keywords and a call to action.
Example of a correct implementation:
Missing Open Graph tags
What it means: Open Graph tags determine how the page looks when shared on social networks. Without them, an unattractive and incomplete preview is often shown, which makes users less inclined to share.
How to fix it:
- Add at least the basic OG tags to the head: title, description, image and url.
- Choose a representative image of suitable dimensions (1200x630 px).
- Make sure the OG tags are relevant and consistent with the page content.
Example of a correct implementation:
Hreflang problems (missing self-reference and return link)
What it means: Hreflang tags identify the language and regional versions of a page. For them to work correctly, every page must contain links to all of its language variants, including a link to itself. The links must also work in both directions so that Google correctly identifies all versions.
How to fix it:
- Create a complete set of hreflang links for all language versions.
- Place this block in the head of every language version of the page.
- Include an x-default link for the default variant as well.
Example of a correct implementation for three languages:
Modern content management systems (CMS) are designed to make managing a multilingual website as simple as possible. As the attached image shows, the different language versions of a single page (in this case the login page) can be managed easily in the system's administration.
Missing Twitter card (X Cards)
What it means: The X network uses special meta tags for attractive, prominent link sharing (Twitter Cards). Without them a share appears as just an ordinary link, which reduces reach and user interest.
How to fix it:
- Choose the card type (most often summary_large_image for a large preview).
- Add the relevant twitter: meta tags to the head.
- Ideally use your own Twitter account (twitter:site).
Example of a correct implementation:
Missing x-default hreflang annotation
What it means: X-default tells search engines which version of the page to show users whose language or region is outside your defined variants. Without it, Google may show an unsuitable version.
How to fix it:
- Add a link with hreflang="x-default" to all language versions.
- It usually points to the most universal version of the website.
Example of a correct implementation:
Incorrect URL structure with parameters
What it means: URLs should be simple and contain keywords. If unnecessary parameters (such as session IDs or filters) get into the URL, this can cause duplicate content and confuse search engines.
How to fix it:
- Optimise URLs so that they are as short and readable as possible.
- Remove unnecessary parameters or set them to be ignored in Google Search Console.
- If parameters are necessary, use canonical tags pointing to the main version of the URL.
Example of a correct URL:
example.com/products/womens-running-shoes-Brand
Not using the canonical tag
What it means: Canonical tags tell search engines which URL is the primary one when several versions of the same content exist. Without them you risk a penalty for duplicate content.
How to fix it:
- Set a canonical tag on every page pointing to its preferred URL. At the very least this is advisable on all pages with any potential for duplication, such as filtering or print versions.
- Make sure the canonical points to a fully qualified URL (including protocol and domain).
Example of a correct implementation:
Hreflang points to a non-canonical URL
What it means: Hreflang should point to the main (canonical) version of the page in the given language. If it leads to a non-canonical URL (for example with UTM parameters), Google receives a confusing signal and may ignore the hreflang.
How to fix it:
- Check all hreflang links on the website.
- Verify that they point to the truly canonical URL.
- Remove parameters and redirects from the target addresses.
Example of a correct implementation:
Hreflang leads to a redirect or an error
What it means: If hreflang points to a URL that redirects or returns an error (404, 500), Google cannot properly verify the language versions and the hreflang stops working.
How to fix it:
- Check all hreflang URLs with an SEO tool.
- Verify that they return a 200 OK status code.
- Fix the errors and redirects so they point to the correct final addresses.
An indexable page has become non-indexable
What it means: A page that used to bring in traffic is now blocked for search engines (for example by a meta noindex or robots.txt). The result is lost visibility and traffic.
How to fix it:
- Regularly check important pages for noindex tags.
- Check the headers and robots.txt as well.
- Remove the blocks on pages that should be indexable.
Orphan pages
What it means: Pages with no internal links pointing to them are hard for search engines to discover and have little chance of ranking well. Use a tool such as Screaming Frog, which crawls your website the same way Googlebot does, by following every link from the home page. It then compares this list with the complete list of all URLs it knows about (for example from your sitemap, Google Analytics or Google Search Console). Pages that appear in the complete list but were not found by the crawler are orphans.
How to fix it:
- Identify orphan pages with a crawler (such as Screaming Frog).
- Add relevant internal links to them.
- Make sure they are reachable within 3–4 clicks of the home page.
One page listed for several languages in hreflang
What it means: If the same URL is marked up for several languages, Google receives a confused signal and may ignore the whole hreflang block.
How to fix it:
- Make sure every language has a unique URL.
- If a language version does not exist, do not list it in hreflang.
Example of a correct implementation:
Canonical URL leads to an error or a redirect
What it means: The canonical tag should point to the final, valid page. If it leads to an error (404, 5xx) or a redirect, Google may ignore it.
How to fix it:
- Check the status of all URLs listed in canonical tags.
- Adjust the links so that they lead to the working, final version (200 OK).
Canonical URL from HTTP to HTTPS
What it means: The canonical tag on an HTTP page points to the HTTPS version. This is not an error, but it indicates that a 301 redirect is missing.
How to fix it:
- Set up a permanent 301 redirect from HTTP to HTTPS at server level.
- Make sure HTTPS is the default version of the website.
Canonical URL from HTTPS to HTTP
What it means: A secure HTTPS page lists the insecure HTTP version as its canonical. This is a serious error and can damage indexing.
How to fix it:
- Fix all canonical tags on HTTPS pages.
- Always use HTTPS as the canonical address too.
Example of a correct implementation:
Canonical URL leads to a 404 error
What it means: The canonical tag points to a page that does not exist, which can hurt indexing.
How to fix it:
- Verify all canonical URLs with a tool such as Screaming Frog or GSC.
- Remove those that lead to a 404 error.
- Replace them with valid, working URLs.
Meta refresh redirect
What it means: This is an outdated redirect performed in the browser, which harms both SEO and UX.
How to fix it:
- Find all meta refresh tags.
- Replace them with a server-side 301 redirect (for example via .htaccess).
Changed meta title or description
What it means: SEO tools monitor key elements such as <title> and <meta name="description">. Every change usually has a major impact on search performance and CTR.
How to fix it:
- Find out whether the change was planned (for example an A/B test or a change of strategy).
- If so, monitor the trend in GSC (positions, impressions, CTR).
- If not, find the cause and, where appropriate, restore the original optimised version.
Meta title does not match the one in the results
What it means: Google sometimes rewrites the title if it is not relevant enough to the query.
How to fix it:
- Check which title Google used.
- Adjust the
<title>so that it is more descriptive, shorter and natural. - Recommended length: 55–60 characters
Redirect leads to a broken page
What it means: A redirect (for example a 301) leads to a URL that returns a 404 or 500 error. This destroys link value as well as the user experience.
How to fix it:
- Audit all redirects with an SEO crawler.
- Fix the target address or remove the broken redirect.
Mismatch between hreflang and lang
What it means: The language signals in hreflang and lang do not match, which confuses search engines.
How to fix it:
- Make sure that
hreflang="cs"matches<html lang="cs">. - Check every language version.
Invalid language codes in hreflang or lang
What it means: Incorrect syntax (for example cz instead of cs) causes the search engine to ignore these directives.
How to fix it:
- Use ISO 639-1 (language) and ISO 3166-1 Alpha-2 (region), for example
cs-CZ. - Use a hyphen
-rather than an underscore.
Correct:
hreflang="cs-cz" | lang="cs"
A non-canonical page is marked as canonical
What it means: A page with parameters or duplicate content has a canonical tag pointing to itself instead of to the main URL.
How to fix it:
- The canonical URL must always point to the "clean", main version of the content.
The page contains too little text
What it means: Search engines rate the content as low value ("thin content"), which reduces the chances of ranking well.
How to fix it:
- Identify pages with a low word count.
- Add quality content: descriptions, guides, reviews, FAQs and so on.
Content is not properly adapted for mobile
What it means: On mobile devices the content is hard to read and requires scrolling or zooming. This hurts both SEO and UX.
How to fix it:
- Make sure the correct viewport tag is in the
<head>:
<meta name="viewport" content="width=device-width, initial-scale=1.0">
- Use responsive CSS (Flexbox, Grid, media queries).
- Test the layout on different devices.
If you are not sure how to set up your website correctly and optimise SEO effectively for different language versions, we will be happy to advise you. We can help not only with quality translation and localisation but also with the technical side, such as sound SEO practices, URL structure, the use of hreflang tags and other factors that improve your website's visibility in search engines. Get in touch and together we will make sure your multilingual website is accessible, attractive and easy to find for users from different language regions.