Encountering the “520 Web Server Returned an Unknown Error” can be perplexing as it indicates that the server received an unexpected response. This error typically occurs when the origin server returns an empty, unknown, or unexpected response.


Causes of the “520 Web Server Returned an Unknown Error”

1) Server Overload:
The server is overwhelmed by too many requests.

2) DNS Issues:
Misconfigured DNS settings or DNS server errors.

3) Firewall Restrictions:
Overly restrictive firewall settings blocking legitimate requests.

4) Server Configuration Issues:
Misconfigured server settings leading to unexpected responses.

5) Software Crashes:
Server software crashes causing it to send incomplete responses.


How to Fix the “520 Web Server Returned an Unknown Error”

1) Check Server Load:

  • 🔹 Monitor Load: Use server monitoring tools to check if your server is overloaded. Tools like Nagios or New Relic can help.
  • 🔹 Reduce Load: Optimize your code, use load balancing, or upgrade your server resources if necessary.

2) Review DNS Settings:

  • 🔹 Check Configuration: Ensure your DNS settings are correct. Use tools like dig or nslookup to verify DNS records.
  • 🔹 Update Records: If needed, update your DNS settings through your DNS provider.

3) Adjust Firewall Settings:

  • 🔹 Verify Settings: Check your firewall settings to ensure legitimate traffic isn’t being blocked. Tools like UFW for Linux can help.
  • 🔹 Whitelist IPs: Make sure to whitelist IP addresses that need access.

4) Check Server Configuration:

  • 🔹 Review Config Files: Look for misconfigurations in server config files (e.g., httpd.conf for Apache or nginx.conf for NGINX).
  • 🔹 Correct Errors: Make any necessary corrections to ensure the server is configured properly.

5) Restart Server Software:

  • 🔹 Restart Services: Use commands like sudo systemctl restart apache2 or sudo systemctl restart nginx to restart your web server.
  • 🔹 Check Logs: Review server logs for any errors that might need attention. Logs are usually found in /var/log/.


Preventing the “520 Web Server Returned an Unknown Error”

1) Regular Monitoring:
Monitor server load and performance regularly.

2) Proper Configuration:
Ensure server and DNS settings are correctly configured.

3) Update Software:
Keep server software up to date to prevent crashes and bugs.

4) Firewall Management:
Manage firewall settings to avoid blocking legitimate traffic.

By understanding and addressing the “520 Web Server Returned an Unknown Error,” you can maintain a smoother browsing experience and ensure your website runs efficiently. If you need further assistance, don’t hesitate to contact our support team.