What can cause a 500 Internal Server Error?

Eva Claes
Technical Copywriter
January 25, 2024

Encountering a 500 Internal Server Error can be like hitting an unexpected roadblock, leaving both users and developers puzzled. It's that moment your website greets visitors with something other than what they came for: frustration. You know it's crucial to solve, but where to start? This article demystifies the dreaded 500 Internal Server Error by breaking down its causes and offering proactive solutions. With a focus on server-side issues, we'll guide you through common culprits and arm you with step-by-step diagnostics. By article's end, you'll not only troubleshoot with confidence but also embrace strategies to keep such errors at bay – ensuring a smoother sail for your website's future.

Understanding the 500 Internal Server Error

A 500 Internal Server Error is a generic error message indicating that something has gone awry on the website's server, but the server could not pinpoint the exact issue. When you encounter this error, typically, the server has stumbled upon an unexpected condition that prevented it from fulfilling the request made by the client. Importantly, this is a server-side issue, meaning the problem isn't likely to stem from your end or your device.

Impact on User Experience

This kind of error can significantly deteriorate user experience. When a 500 Internal Server Error occurs, users are left in the dark because the server provides no specific information about the root of the problem. This can lead to frustration and might discourage users from returning to the website. For a website owner or operator, understanding and resolving these errors is essential to ensure a smooth, uninterrupted user journey.

Server-Side vs. Client-Side Errors

Errors on the internet are often divided into two categories: server-side and client-side. Client-side errors entail issues with the user's setup – the likes of an incorrect URL (a 404 error), or problems with client-side scripts or cached data. In contrast, server-side errors happen on the web server where the website is hosted. As an IT enthusiast, you should be aware that while you can often fix client-side issues by rechecking URLs, clearing your cache, or updating your browser, server-side problems, such as the 500 Internal Server Error, require intervention at the server level – usually by a web developer or server administrator.

Common Causes of 500 Internal Server Errors

At the heart of a 500 Internal Server Error are often server misconfiguration issues. These might include incorrect permissions, invalid directives within configuration files, or improper settings in .htaccess and php.ini files. For instance, a faulty line in your .htaccess file could read as follows:

RewriteRule ^(.*)$ index.php/$1 [L,QSA]

If mod_rewrite is not enabled on your server, this could cause an internal server error because the server does not know how to handle the directive. Ensuring that configurations match the requirements of your hosted applications is crucial.

Errors can also stem from scripting and coding issues in web applications. A missing semi-colon, incorrect syntax, or calling an undefined function could all lead to internal server errors. Consider this PHP snippet:

$variable = SomeFunction(;

The absence of a closing parenthesis and the lack of a semicolon after the function call will trigger a 500 error because the PHP code is invalid. Always check code thoroughly, and consider using automated tools for syntax validation to help spot these errors. If you have installed any Wordpress plugins or edited the PHP code recently, check to make sure it is valid.

Lastly, server resource limitations play a significant role. When your application demands more memory or processing power than the server can provide, it can cause crashes or unresponsive scripts. For applications written in languages like Python or PHP, you might see errors in the logs revealing memory limits being hit, prompting you to adjust your php.ini settings:

memory_limit = 256M

By understanding these common triggers, you'll be better equipped to identify and resolve issues that lead to a 500 Internal Server Error, keeping your site's uptime optimal.

How do I stop 500 Internal Server Error?

Stopping a 500 Internal Server Error involves a diligent step-by-step diagnostic process. Firstly, you'll want to delve into the server configuration files. For instance, if you're using an Apache server, errors could lie in the .htaccess file. It's essential to carefully check for any syntax errors; even a misplaced character can cause trouble. You can utilize tools like apachectl configtest to scan for these issues. Here’s a simple command snippet you might run in your server's console:

apachectl configtest

Likewise, if you're on an NGINX server, scanning the configuration files with nginx -t would be your go-to command:

nginx -t

Turning attention to your code, make sure to review the changes performed prior to the error's appearance. Revert recent edits one by one and test if the server responds correctly after each reversal.

Monitoring server health is critical. Regularly check error logs for clues; they are often located in /var/log/apache2/error.log for Apache and /var/log/nginx/error.log for NGINX. Not only do these logs provide descriptions of the error, but they also pinpoint their location in your code or configuration.

It's also prudent to utilize website monitoring services, capable of alerting you to server issues as they occur—ensuring you can react swiftly.

When testing fixes, replicate the conditions that provoked the error. Use command line tools like curl to send requests and check for a proper server-side response:

curl -I http://YourDomain.com

By methodically working through these steps, you’ll not only resolve the issue at hand but also arm yourself against similar issues reoccurring. Remember, patience is key; fixing server errors is often a process of trial and error.

Preventing Future 500 Internal Server Errors

Staying proactive can significantly reduce the frequency of 500 Internal Server Errors. Implementing routine server maintenance is one of the strongest defenses against unexpected server issues. This includes regularly checking server resources, such as available disk space, memory usage, and CPU load. Too often, these fundamental factors are the culprits behind server failures. For instance, poor memory management in scripts can lead to memory leaks. Regularly reviewing performance logs helps identify such trends that might indicate trouble brewing.

It is invaluable to use website monitoring services that offer real-time alerts for server errors. These services keep a vigilant eye on your website, notifying you instantly if a 500 Internal Server Error arises, often before users notice. Being alerted immediately enables you to begin troubleshooting right away, reducing downtime. Services such as WatchSumo can continuously monitor your website, and alert you before problems start.

Moreover, consistently updating software and scripts is crucial. Developers often release updates when they fix bugs that could otherwise lead to server errors. Keep your server's operating system, content management system, and any scripts or applications up to date. Establish a schedule and procedure for updates to ensure they are methodically applied. By faithfully maintaining, monitoring, and updating your systems, you mitigate risks that can cause server errors and maintain a more stable and reliable website environment.


In essence, the dreaded 500 Internal Server Error is a cry for help from your server, indicating that something went awry without pointing to a specific fault. From server misconfiguration and resource limitations to coding blunders, these gremlins can disrupt the smooth experience users expect. As you've seen, the key to banishing them lies in systematic diagnostics, vigilant monitoring, and robust coding practices. Regularly reviewing your server's configuration, keeping a keen eye on error logs, and implementing real-time monitoring services are indispensable strategies for maintaining a healthy website ecosystem. When writing code, always aspire for quality and resilience, and test exhaustively to fortify against unwelcome surprises. By adhering to these best practices and fostering a proactive maintenance culture, you poise yourself to quickly squelch out these errors, keeping your digital domain accessible and efficient for all its visitors.