An sudden connection closing by the client (often a browser or other software) before the server could finish processing the request is shown by a Nginx error code 499. At Bobcares, we assist our customers with several NGINX queries on a daily basis as part of our Server Management Services.

Overview

1. Fixing Nginx Error code 499
2. Common Causes
3. Troubleshooting Steps

Fixing Nginx Error code 499

This occurs when the client (like a browser) closes the connection before the server finishes processing. It indicates an issue on the client side, unlike a typical 502 Bad Gateway error.

Common Causes

1. Client-side Timeout: The client’s connection times out while waiting for a server response.

2. User Canceled Request: The user stops the request in their browser or application.

3. Network Issues: Instability or interruptions cause the connection to drop.

4. High Server Load: Overloaded servers take longer to process requests, leading to timeouts.

5. Conflicting Requests: Multiple requests from the same client interfere with each other.

Troubleshooting Steps

1. Check Logs:

tail -f /var/log/nginx/access.log

2. Increase Client Timeout:

http {
send_timeout 120s;
…
}

3. Optimize Server Performance: Improve backend services and Use caching for faster responses.

4. Monitor Client Behavior: Identify if specific clients or actions cause errors and optimize those areas.

5. Check Load Balancer Configuration: Ensure it’s set to handle long-running connections and timeouts.

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Conclusion

To sum up, NGINX Error Code 499 shows that a client has closed the connection before the server was able to send a response. Here, we’ve provided the troubleshooting steps from our Tech team.