HTTP status codes like 404 (Not Found) or 500 (Internal Server Error) are common and known but the 499 HTTP code is less known and can be particularly difficult to understand.  

The 499 HTTP status code usually occurs with Nginx and means the client closed the connection before the server could respond. This happens when a user navigates away from a page before it fully loads. 

Let us dive deeper to explore what the 499-status code is, its main causes and how you can fix it. 

What is the 499 Status Code? 

The HTTP 499 status code is also known as a “client closed request” and it is a special case of 502 Bad Gateway Error. It means that the client has closed the connection while the server is still processing the request made by the client.  

HTTP 499 is categorized under client-based errors, and it means that the issue is on the client side. Other common errors that are included in this category are: HTTP 404 Not Found and HTTP 400 Bad Request. The problems with the following errors are common and are easy to define whereas HTTP 499 is more general. 

The error can happen on both Nginx and Apache servers, but it is more common on Nginx servers as it was created by Nginx. It is more common on it because the server software handles client connections differently than Apache. With Nginx, each client connection is processed in a separate thread and hence if one client connection takes a long time to process then it will not slow down the other clients.  

However, with Apache, the client connections are processed in the same thread which can cause problems if one client takes a comparatively longer time because it will slow down all the other clients.  

What are the Main Causes of an HTTP 499 Error? 

Understanding the causes of an HTTP 499 error is crucial for troubleshooting and resolving the issue. Here are the primary reasons why this error might occur: 

  • User Action: The most straightforward cause of the error is user action. A user might decide to stop the request by closing the browser tab, clicking on a different link, or hitting the stop button before the server completes its response. 
  • Request Timeout: The client might timeout and close the connection if a request takes too long to process. This can happen if the server is under heavy load or if the request is particularly complex. 
  • Network Connectivity Problems: These can cause the client to lose connection with the server, resulting in a 499 status code error. 
  • Long Processing Times: Requests that take a long time to process, such as file uploads or queries to a database, often lead to clients timing out or losing patience and aborting the request. 
  • Client-Side Scripts: Also known as JavaScript, they can sometimes terminate requests prematurely if they encounter errors or are designed to abort requests under specific conditions. 

How To Fix the HTTP 499 Error 

Now that we understand the HTTP 499 error, fixing a HTTP 499 error involves addressing the causes, which can vary.  

Following are some potential steps an individual can take to resolve 499 errors: 

Temporary Solutions 

As mentioned above, this error may be a temporary issue and it can be resolved by simply trying to load the page again. It might be that your host or the server is overloaded. Therefore, it is recommended that you clear your browser cache and try again to check if the issue is resolved. 

Plugin Issues 

Some users report that certain plugins cause the HTTP 499 status code error. Therefore, temporarily disabling plugins is recommended to check if it resolves the HTTP 499 error. This process will deactivate all plugins on your WordPress site. You can revisit your website to see whether the error message is still showing. If not, you can try activating your plugins one by one until you find the tool causing the issue. 

Error Log Analysis 

It is essential to leverage your error logs when you troubleshoot the HTTP 499 code. This approach will make it easier to narrow down the issue and determine whether it results from a specific plugin or tool. You can also enable and view error logs by turning on WordPress debugging mode. 

 Hosting Environment 

When you manage a website, it is important to have reliable solutions for identifying and troubleshooting errors on your site. Sometimes the HTTP 499 errors can occur when a request is cancelled because it takes too long. Some hosting providers use a “kill script.” It forces a request to be terminated after a certain amount of time. This script is often used in shared hosting environments to prevent long requests from impacting other sites. 

Proxy or Load Balancer 

However, it is important to note that the “client” may be a proxy, such as a Content Delivery Network (CDN) or load balancer. A load balancing service can act as a client to the Nginx server and proxy data between your server and users. This can cause a timeout that cancels the request to the Nginx server. 

PHP Configuration 

PHP timeouts happen if a process runs longer than the maximum execution time (max_execution_time) or max_input_time specified in your server’s PHP configuration. You may encounter timeouts if you have a busy website or scripts that need longer execution times. Therefore, it might be necessary to extend your timeout value. It is wise to check with your host about the values set on your server. 

To reduce 499 status code errors, focus on optimizing your server and application performance, increasing timeout settings, and ensuring a reliable network. Handling long-running requests better and providing users with progress indicators can also help. 

Also, the quality of your hosting provider can directly impact the occurrence of these errors. A reliable hosting provider with strong infrastructure and performance features like load balancing and caching can help prevent issues such as server overload or timeouts that lead to 499 errors. By choosing a reputable website hosting provider, you are investing in a foundation that can better handle the demands of your website, reducing the likelihood of encountering 499 errors and improving overall performance. 

By understanding and addressing the causes of 499 errors, and investing in quality website hosting, you can enhance your website’s reliability and user experience.