Why Your WordPress Website Has 404 Errors on Pages That Used to Work

If your WordPress website suddenly starts showing 404 errors on pages that used to work, it usually means something has changed in the way those pages are being found, linked, or loaded.

This can be frustrating because the page may have been working perfectly well for weeks, months, or even years. Then without much warning, visitors start landing on a “Page Not Found” message instead of the content they expected.

For a small business website, that matters more than people think. Broken pages can damage trust, interrupt enquiries, waste traffic, and quietly hurt SEO if they are left unresolved.

This guide explains the most common reasons WordPress pages start showing 404 errors, what to check first, and when it makes sense to get help through my WordPress fixes or wider website fixes service.

What does a 404 error actually mean?

A 404 error means the browser reached your website, but the specific page being requested could not be found at that URL.

That is important.

It does not usually mean the entire website is down. It means a particular page, post, product, category, or file is no longer available where WordPress or the user expected it to be.

That can affect:

• service pages
• blog posts
• product pages
• category pages
• images or media files
• old URLs from search results
• links from other websites
• internal links across your own website

If a page used to work and now returns a 404, something has usually changed in the background.

Common signs of this problem

This issue often shows up in one or more of these ways:

• a page opens fine one day, then shows Page Not Found the next
• old blog posts or service pages stop working
• links from Google lead to broken pages
• internal links on your own site now return 404s
• products or categories disappear
• only certain pages are broken while the rest of the site works
• the problem started after changes to the website

Sometimes this affects a single page. Sometimes it affects whole sections of the site.

1. The page URL may have changed

This is one of the most common causes.

If the slug or URL of a page has been changed, the old address may no longer work unless a redirect was put in place.

That often happens when:

• a page title is edited
• a slug is changed manually
• a blog post URL is tidied up
• product or category URLs are renamed
• someone reorganises the site structure

From WordPress’s point of view, the old URL may no longer exist. So even though the content is still on the site somewhere, the old address now leads to a 404.

2. Permalink settings may have been disrupted

WordPress relies on permalink settings to generate page URLs properly.

If those settings become disrupted, pages that should exist can start returning 404 errors even though the content is still present in the admin area.

This can happen after:

• a migration
• a plugin change
• a server change
• a manual edit
• a restore from backup
• an update that affected site structure

This is one reason why pages can appear to “vanish” even though they have not actually been deleted.

3. The page may have been deleted, unpublished, or moved to draft

Sometimes the simplest answer is the right one.

A page may start showing 404 because it has been:

• deleted
• moved to trash
• changed to draft
• set to private
• removed during a redesign
• replaced with a new page without redirecting the old one

This happens more often than people realise, especially on websites with multiple people editing content or on older sites that have gone through several rounds of changes.

4. A plugin conflict may be interfering with URLs

WordPress plugins can affect URL behaviour in all sorts of ways.

A plugin conflict can sometimes cause 404 issues involving:

• custom post types
• categories and tags
• WooCommerce products
• redirects
• multilingual pages
• security rules
• caching behaviour

This is especially common after updates, which is why it is worth checking Why WordPress Websites Break After Plugin Updates if the problem appeared after a change.

5. Redirects may be missing, broken, or conflicting

If a page has moved, there should usually be a proper redirect from the old URL to the new one.

Without that, visitors and search engines trying to reach the old address may just hit a 404.

This often becomes a problem after:

• redesigns
• URL clean-ups
• page mergers
• service page rewrites
• product changes
• changes to category structures

Sometimes redirects exist but are set up badly. In those cases, pages may go to the wrong place, loop, or fail completely. If that sounds familiar, it is also worth reading Why Your WordPress Website Is Redirecting to the Wrong URL.

6. The issue may have started after changing the site URL or domain setup

URL problems often follow bigger website changes.

For example:

• switching from HTTP to HTTPS
• changing the main site URL
• moving from staging to live
• changing domain settings
• switching from www to non-www
• migrating to new hosting

If those changes are not handled cleanly, WordPress can end up serving 404 errors on pages that used to work.

If that timing fits your issue, it is worth checking Why Your WordPress Website Broke After Changing the Site URL.

7. Internal links on your own site may now be pointing to old URLs

Sometimes the page itself is fine, but your internal links are outdated.

That means:

• the page exists at a new address
• but menus, buttons, blog links, or service-page links still point to the old address
• so users keep landing on a 404

This is more common on sites that have been edited in pieces over time, where some links were updated and others were not.

That is one reason internal linking matters so much. A site can look fine on the surface while still containing broken paths underneath.

8. Google may still be showing an older URL

Sometimes a page returns 404 simply because Google still has an old version of the URL indexed.

That can happen if:

• a page was renamed
• content was consolidated
• the site structure changed
• redirects were not added properly
• the page was removed without replacement

From the user’s point of view, it looks like “Google is sending people to a broken page”. In reality, the search result may just be pointing to an address that no longer exists.

That is one reason 404 issues can overlap with Why Your WordPress Website Is Not Showing Up on Google and broader indexing problems.

9. WooCommerce products, categories, or custom post types may be involved

On more complex websites, 404 errors are not always about normal pages.

They can also affect:

• WooCommerce products
• product categories
• portfolio items
• testimonials
• event pages
• other custom post types

In those cases, the problem may be tied to:

• plugin configuration
• rewrite rules
• permalink refresh issues
• disabled post type settings
• theme conflicts
• post type registration problems

This is one reason ecommerce or more customised WordPress sites can develop strange 404 patterns after updates or setup changes.

10. Caching can make the issue look inconsistent

Caching does not usually create 404 errors by itself, but it can make them harder to understand.

For example:

• one device sees the page working
• another sees a 404
• one user sees an older cached version
• the site seems fixed, but the old 404 still appears in some places

That can make troubleshooting much more confusing than it should be.

If your site has also had problems showing updates properly, Why Your WordPress Website Is Not Showing Recent Changes may be relevant too.

What to check first

If pages that used to work are now showing 404 errors, this is the order I would usually work through it:

1. Confirm whether the page still exists in WordPress

Check whether the page, post, product, or category is still published.

2. Check whether the URL changed

Compare the old URL with the current live one.

3. Test whether the issue affects one page or many

If it affects several pages, that points more strongly toward a permalink, plugin, or site-wide configuration issue.

4. Review recent changes

Think about whether this started after:

• a plugin update
• a redesign
• a migration
• changing page slugs
• editing menus or structure
• changing the site URL

5. Check internal links and menus

Make sure your own website is not still linking to outdated URLs.

6. Check redirects

If an old page was replaced or renamed, there should usually be a proper redirect.

7. Look for broader site instability

If the site has had other issues such as redirect problems, update problems, or broken layouts, the 404 issue may be one part of a wider technical problem. In that case, it is also worth reviewing What to Check First When a WordPress Website Breaks.

Why this matters for SEO and enquiries

404 errors matter because they interrupt both user journeys and search visibility.

If important pages are broken, that can lead to:

• visitors leaving the site
• fewer enquiries
• lost trust
• wasted traffic from Google
• broken internal linking
• weaker crawling of the site
• missed conversions from pages that used to perform well

Not every 404 is a disaster. Some are natural over time. But when valuable or previously working pages start failing, it should be treated as a real issue.

When this is likely to be urgent

This should usually be treated as urgent if:

• service pages are affected
• enquiry pages are affected
• product pages are affected
• old URLs from Google are broken
• multiple pages are failing at once
• the issue appeared after a website change
• traffic or leads may be being lost

In those cases, the goal should be to restore the right pages and fix the root cause, not just patch over the symptoms.

When to get help

If your WordPress website has 404 errors on pages that used to work, and you are not sure whether the cause is URL changes, permalinks, redirects, deleted content, plugin conflicts, or a wider site issue, it usually makes more sense to diagnose it properly than to keep guessing.

That is especially true if:

• the site is important to the business
• the issue affects key pages
• the problem started after a change
• several pages are involved
• you are not sure which URLs should exist and which should redirect

If the issue is WordPress-specific, my WordPress fixes service is the best place to start. If the problem is broader and tied to redirects, structure, or general website changes, my wider website fixes service may be more suitable.

Final thought

If pages that used to work are now showing 404 errors, it usually means something has changed in the way WordPress is handling those URLs.

Sometimes the cause is simple, like a renamed page or missing redirect. Sometimes it is a permalink issue, plugin conflict, migration problem, or broader structural change.

The important thing is to fix the cause properly.

A business website should not be sending visitors to dead ends, especially on pages that used to carry traffic, trust, or enquiries. If you need help sorting it properly, take a look at my WordPress fixes service, check my website pricing, or get in touch.