Case Study: Solving the ‘Sitemap Could Not Be Read’ Error for a 500K+ Page Website

When you’re managing a large-scale website with over 500,000 pages, getting everything properly indexed in Google is always a challenge. I recently worked on an Australia-specific website built on Laravel, and one of my first priorities was to make sure all those pages were correctly submitted to Google Search Console (GSC).

To do this, we created multiple XML sitemaps and submitted them through GSC. But instead of smooth indexing, I was met with a frustrating error message:

“Sitemap could not be read.”

Sitemap could not be read

At first, a few sitemaps went through without any issues, but the majority kept failing. If you’ve ever run into this problem, you know how discouraging it feels — especially when you’re working on a big project where indexing efficiency directly impacts visibility in search results.

In this post, I’ll break down what this error actually means, why it happens, and how I ultimately solved it for this half-a-million-page website.

Sitemap could not be read.

2. What the Error Means

The “Sitemap could not be read” error in Google Search Console doesn’t always mean your sitemap is completely broken. It simply means Googlebot was unable to access or process it correctly.

Here are the most common reasons this error shows up:

  • Invalid Sitemap Format → The file isn’t a proper XML sitemap (e.g., wrong tags, encoding issues, or not following the protocol).
  • Server Issues → The sitemap URL returns errors like 403 (forbidden), 404 (not found), 500 (server error), or times out before Google can fetch it.
  • Redirects in Sitemap URL → If the sitemap link redirects (HTTP → HTTPS or www → non-www), GSC may fail to read it.
  • Blocked by Robots.txt or Headers → Sometimes the sitemap file is accidentally blocked from crawling.
  • File Size or URL Limits → A single sitemap can only hold up to 50,000 URLs or be 50MB in size. Anything bigger needs to be split into multiple sitemaps.

My Investigation Process

1. Checking Sitemap Format & Structure

The first thing I did was review the sitemap’s XML formatting. Sometimes, missing opening/closing tags or small syntax errors can break a sitemap. After going through it carefully, I confirmed that everything looked correct.

Since this was a large sitemap, I decided to test a smaller version. I stripped it down to just 100 URLs and submitted it — but to my surprise, I still got the same error in Google Search Console.

2. Inspecting HTTP Headers

Next, I checked the HTTP response headers for the sitemap. That’s when I found an issue:

Incorrect header: Content-Type: text/html (expected: application/xml)

Since we usually work on WordPress projects, headers like this are handled automatically. But because this site was built on Laravel, the configuration was incorrect. I fixed it via the .htaccess file so the headers would serve the sitemap correctly.

# Force .xml files to serve as proper XML
AddType application/xml .xml

Even after fixing the headers, GSC was still showing the same error.

3. Validating with an XML Sitemap Checker

To be sure, I ran the sitemap through My Sitemap Generator’s validator.

The validator confirmed the sitemap was valid and correctly formatted. This told me the issue wasn’t with the sitemap file itself.

valid and correctly formatted

I also went through a quick checklist:

  • ✅ Sitemap returned a 200 status code
  • ✅ Sitemap located at the root of the site
  • ✅ Sitemap URL added in robots.txt
  • ✅ No redirects on the sitemap URL
  • ✅ Sitemap not blocked by robots.txt
  • ✅ XML parsing was correct

Just to be sure, I submitted the sitemap in Bing Webmaster Tools and Yandex — and both crawled and processed the sitemap successfully. This gave me confidence that the issue was isolated to Google Search Console.

4. Looking for External Insights

While researching, I came across a Google SEO Office Hours (March 5, 2021) where John Mueller mentioned that sometimes simply changing the sitemap filename/URL can reset Google’s processing and “reset their opinion” of the file.

This gave me a clue — maybe the issue wasn’t the content of the sitemap but the way Google was handling the filenames.

5. Discovering the “Sitemap Number Bug”

Digging deeper, I found reports (via Screaming Frog in late 2023/early 2024) of a “sitemap number bug.”

This happens when sitemap filenames use a hyphen followed by multiple digits, for example:

  • /sitemap-10.xml
  • /sitemap-25.xml

Google’s systems sometimes fail to parse these filenames, leading to “Sitemap could not be read” errors.

Our sitemaps were following a similar pattern.

6. Fixing the Laravel Sitemap Setup

While investigating, I also discovered another issue: the Laravel dev team had configured the system to compile sitemaps in real time. This caused delays whenever Google tried to fetch them.

To fix this, I worked with the devs to:

  • Generate static sitemaps instead of on-the-fly ones.
  • Set up a nightly sitemap refresh for updated content.
  • Rename sitemap files to avoid the hyphen + multiple digits issue.

The result? Blazing fast load times and Google Search Console finally accepted the sitemaps without errors.

Key Takeaway

In my case, the solution was a combination of fixing headers, avoiding the filename bug, and switching to static sitemaps. After making these changes, the “Sitemap could not be read” error was resolved, and indexing improved significantly for this 500K+ page Laravel site.

If you’ve faced a similar issue, I’d love to hear how you solved it — feel free to drop your experience in the comments.