Quick Summary
Error 522 means that the TCP connection between Cloudflare and the origin web server timed out. This often indicates that Cloudflare successfully connected to the origin, but the origin did not reply with an HTTP response before the connection timed out.
Common Causes
- Origin Server Overload: The origin server is overloaded and can't respond to requests in a timely manner. This could be due to high CPU usage, insufficient memory, or a large number of concurrent requests.
- Web Server Issues: The origin web server (e.g., Apache, Nginx) is not functioning correctly. It might be crashed, misconfigured, or have resource limitations.
- Network Connectivity Issues: There are network connectivity problems between Cloudflare and the origin server. This could involve routing issues, firewall restrictions, or temporary outages.
- Long-Running Processes: A process on the origin server is taking too long to complete, such as a database query or external API call. This ties up resources and prevents the server from responding to Cloudflare.
- DDoS Attack: The origin server is under a DDoS attack, overwhelming its resources and preventing it from responding to legitimate requests.
- Incorrect DNS Settings at Cloudflare: Although less common, incorrect DNS configurations on Cloudflare can disrupt communication with the intended origin server, including issues with SSL/TLS.
Step-by-Step Fixes
Method 1: Check Origin Server Load
Step 1: Log in to your origin server and monitor its resource usage (CPU, memory, disk I/O).
Step 2: If the server is overloaded, identify the resource-intensive processes and optimize them, or upgrade your server's resources.
Step 3: Consider implementing caching mechanisms to reduce the load on your origin server.
Method 2: Review Web Server Configuration
Step 1: Restart your web server (Apache, Nginx, etc.).
Step 2: Check the web server's configuration files for any errors or misconfigurations.
Step 3: Ensure that the web server has sufficient resources allocated to handle incoming requests.
Method 3: Examine Network Connectivity
Step 1: Use tools like ping and traceroute from a Cloudflare IP address (you can find Cloudflare's IP ranges on their website) to your origin server to check for network connectivity issues.
Step 2: Verify that your origin server's firewall allows traffic from Cloudflare's IP ranges.
Step 3: Contact your hosting provider to investigate any network outages or routing problems.
Method 4: Optimize Long-Running Processes
Step 1: Identify any long-running processes on your origin server.
Step 2: Optimize the code or configuration of these processes to reduce their execution time.
Step 3: Implement timeouts for these processes to prevent them from tying up resources indefinitely.
Method 5: Enable Rate Limiting & Implement Security Measures
Step 1: Implement rate limiting on your origin server to mitigate DDoS attacks and prevent abuse.
Step 2: Use a Web Application Firewall (WAF) to protect your origin server from malicious traffic.
Step 3: Analyze server logs to identify and block suspicious IP addresses.
Method 6: Verify DNS records
Step 1: Double check that the A record on Cloudflare are correctly pointing to your origin server.
Step 2: Check the Cloudflare SSL/TLS settings are correctly setup for Full or Flexible mode.