Stuck with a Cloudflare Error 520 and not sure where it’s coming from? This in-depth guide breaks down what Error 520 actually means, the most common server-side causes (like bad headers or firewall blocks), and how to troubleshoot it with easy-to-follow solutions. Whether you’re a developer, blogger, or website owner, you’ll find real-world fixes, tips, and examples to resolve this frustrating issue quickly — and stop it from coming back.
🔍 Key Highlights
- Error 520 usually pops up when Cloudflare can’t reach your origin server properly.
- It’s not your browser’s fault. It’s typically a server-side problem.
- Learn why it happens, how to diagnose it step-by-step, and what real developers have done to fix it.
- Includes real-life cases, proven solutions, and quick-fix suggestions.
- Packed with Cloudflare-specific tips and common causes.
- Internal and external resources linked to dive deeper.
🙋♂️ So, What Is Error 520?
Let’s not sugarcoat it — seeing “Error 520: Web server is returning an unknown error” when you visit your site is annoying, especially when you’re not sure who to blame — your hosting provider or Cloudflare?
This particular beast is known as the Cloudflare error 520, and it’s basically Cloudflare throwing up its hands and saying: “Hey, I tried to talk to your server, but it gave me a weird response I don’t understand.”
But here’s the good news — it’s fixable. And if you stick around, you’ll walk away knowing exactly how to resolve 520 error messages like a pro.
🧠 What Causes Error 520?
If you’re here, chances are you’ve seen that dreaded white page with a big “520” on it. Cloudflare shows this when:
- Your origin server crashes or restarts unexpectedly.
- There are empty or malformed HTTP headers from your server.
- Your hosting provider’s firewall or mod_security blocks Cloudflare’s IPs.
- There’s a misconfigured SSL setting on either side.
- Cloudflare’s IPs are rate-limited or blocked.
Let’s look at it visually:
Cloudflare ➡ Origin Server “Hey, give me that page for the visitor!” Origin Server: “Umm… [sends garbage or nothing]” Cloudflare: “Error 520 — I have no idea what this is.”
📌 Real example:
Rohit, who runs a WordPress blog on shared hosting, noticed a 520 error showing up every few hours. After digging around, it turned out his server’s PHP-FPM process was crashing intermittently. Fixing that solved the issue. No fancy tools needed — just a bit of observation and logs.
⚙️ How to Fix Error 520 (Step-by-Step 🛠️)
Here’s the part you came for: real-world, actionable fixes.
✅ 1. Check Your Server Logs
Most 520 web server errors are due to your server, not Cloudflare. Look inside:
/var/log/apache2/error.log/var/log/nginx/error.log- Hosting panel logs (like cPanel, Plesk)
Look for clues like: “Connection refused”❗ “Bad header”❗ “Segfault” or crash info❗
✅ 2. Pause Cloudflare Temporarily
This helps narrow down the issue.
- Log into Cloudflare
- Go to your site’s dashboard
- Scroll down to “Advanced Actions”
- Click Pause Cloudflare on Site
Now try accessing your site directly. If the issue persists, your origin server is the culprit.
✅ 3. Whitelist Cloudflare IPs
Sometimes your firewall thinks Cloudflare is an attacker (ironic, right?).
➡ Here’s Cloudflare’s full IP list Add them to your server’s allowlist.
✅ 4. Disable .htaccess Rules or ModSecurity
Overzealous rules in your .htaccess or web application firewall can cause Cloudflare server connection error problems.
Temporarily disable them and see if the 520 error disappears.
✅ 5. Switch SSL/TLS Mode
Try toggling between:
- Full
- Full (Strict)
- Flexible
Sometimes the wrong mode messes up secure connections. Make sure your certificate is valid and your origin server supports HTTPS.
✅ 6. Contact Hosting Support
If you’ve tried the above and still no luck, send this message to your host:
“Hi, I’m getting a Cloudflare error 520. Could you check if your server is blocking Cloudflare’s IPs or crashing when it receives requests?”
They’ll know what to do. (If they don’t, it might be time to find a better host.)
🤖 Common Myths About Cloudflare Error 520
eMyth: It’s a Cloudflare bug. Reality: 95% of the time, it’s a server-side issue — bad headers, firewalls, crashes.
Myth: It’s the browser’s fault. Reality: Browsers don’t even get that far. Cloudflare hits the wall before the page reaches your browser.
Myth: Restarting your PC fixes it. Reality: Nope. You’d have better luck restarting your hosting service.
🧪 Technical Breakdown: 520 Status Code Meaning
Unlike standard HTTP errors like 404 (Not Found) or 500 (Internal Server Error), 520 is unique to Cloudflare.
It’s used when Cloudflare receives an unknown error from your origin server — something that doesn’t map to a typical HTTP status code.
Think of it as a wildcard. Cloudflare says: “I didn’t get a valid HTTP response, just weirdness.”
🧵 Why Does This Matter for Website Owners?
Because your visitors don’t wait around. If your site shows “Cloudflare error 520” too often, they bounce — and Google notices that.
It hurts:
- Your SEO rankings
- Your credibility
- Your conversions
Knowing how to fix HTTP 520 error fast saves traffic, sales, and reputation.
💡 Bonus Tips: Cloudflare 520 Troubleshooting in Action
Here’s what veteran web admins do:
- Use Uptime Robot to monitor when 520 errors happen.
- Combine Logtail or Datadog for real-time log analysis.
- Schedule regular server reboots if memory leaks are common.
- Switch to LiteSpeed or Nginx if Apache crashes often.
🧭 Final Thoughts: You’ve Got This
Error 520 may look intimidating, but now you know it’s not some unsolvable mystery.
It’s usually just:
- A hiccup in your server
- A miscommunication between Cloudflare and your origin
- A firewall playing bouncer a bit too hard
Give your site a bit of TLC, and you’ll bounce back in no time.
📚 Related Reads You Might Find Helpful
- How to Fix the 401 Unauthorized Error – 5 Easy Solutions
- 403 Forbidden Error: What It Is & 7 Easy Fixes to Regain Access
- 402 Error Code (Payment Required): Here’s What It Means & How to Fix It
- 400 Bad Request Error: Here’s What It Means & How to Fix It
- If you’re using Laravel, this guide on Laravel error handling can help you trace backend issues that may trigger Error 520.
If this helped, share it with someone who’s scratching their head over a Cloudflare 520 error. Or better yet, bookmark it. You never know when that white screen might show up again! 😉
