Server Errors Decoded: Understanding and Resolving Top Site Crashes

Server Errors Decoded_ Understanding and Resolving Top Site Crashes

Struggling with server errors can halt your website’s operations. This concise guide demystifies common errors such as the 500 Internal Server Error and 503 Service Unavailable, providing clear causes and direct solutions to help you resolve these issues efficiently and restore your site’s functionality.

Key Takeaways

  • The 500 Internal Server Error is a generic server error message indicating a problem without specifying the exact issue, often caused by programming errors, server overloads, or PHP memory limit breaches, and requires server logs review and troubleshooting steps to resolve.
  • The 503 Service Unavailable error signifies temporary server incapacity often due to high traffic, maintenance, or server communication problems, and can be resolved by server restarts, DNS cache flushing, increasing server resources, or checking Web Application Firewall configurations.
  • A 502 Bad Gateway is indicative of a communication issue between servers and can be managed by checking configurations, ensuring server-proxy reliability, and maintaining proper communication with hosting providers, whereas the 404 Not Found error demands good URL management and a customized 404 page for better user engagement.

Deciphering the 500 Internal Server Error

Server room with multiple server error and network cables

The 500 Internal Server Error message, an HTTP status code, is like a foggy vista. It indicates something has gone wrong on the website’s server, but it doesn’t specify the exact problem. This enigmatic HTTP error message can lead to negative experiences for users across different browsers and operating system and systems, and can also have a detrimental effect on a site’s SEO.

The causes of a 500 Internal Server Error can range from software limitations to general errors indicating temporary or permanent issues. Hence, troubleshooting a 500 error is often likened to solving a mystery due to its broad range of potential triggers and the lack of specific diagnostics in the error message itself.

Identifying the Error on Your Site

Diagnosing a 500 Internal Server Error requires a digital detective mindset. Begin your investigation by examining the web server’s various error messages and logs for details like the error time and specific causative information. Activating the debug mode in a CMS, such as WordPress, can provide detailed error messages, facilitating the identification of a 500 Internal Server Error.

Tools like Trace UI in Apigee Edge or API Monitoring can analyze whether the error was caused by policy execution or by the backend server. NGINX access logs can reveal if a 500 error resulted from within the API proxy or as a response from a request to the backend server.

As a final step, using ‘Down for Everyone or Just Me’ with the website’s domain URL can help determine if the server issue is universal.

Primary Causes Behind the Error

While the spectrum of causes behind a 500 Internal Server Error is broad, some culprits are more common than others. Some common causes of a 500 Internal Server Error include:

  • Programming issues within the website’s code
  • Temporary glitches
  • Exceeding the PHP memory limit on a website, can trigger a 500 Internal Server Error due to the memory each PHP process consumes, with limits imposed by the hosting account.

A server may return a 500 Internal Server Error when it is overloaded and unable to receive a timely response from clients, potentially caused by network latency or insufficient server resources. Server-side errors are indicated by 5xx status codes, which reflect underlying problems with application logic, database interactions, or configuration settings on the server. Encountering 5xx errors on the HTTP status code cheat sheet prompts the need to review server logs, configurations, and application codes for troubleshooting.

Immediate Actions to Mitigate the Issue

Now that we’ve uncovered the causes behind the 500 Internal Server Error, it’s time to explore some immediate remedial actions. Confronted with a 500 Internal Server Error, your initial move should be to:

  1. Refresh the page, ruling out any temporary connectivity glitches.
  2. Purge the browser cache and delete cookies to rectify problems stemming from corrupted cache files.
  3. Inspect or regenerate the .htaccess file, as server configuration files like .htaccess can be the source of 500 errors due to syntax errors.
  4. Reset file and folder permissions to standard values to prevent issues.

Increasing the PHP memory limit is a server configuration adjustment that can resolve errors caused by scripts exceeding available memory. Here are some steps you can take to troubleshoot and fix the issue:

  1. Check the server’s error logs and the hosting control panel for website error logs to get specific details about the error.
  2. Identify any script or file configuration issues that may be causing the error.
  3. Disable WordPress plugins or change the theme one by one to isolate the cause of the error.
  4. Repair or restore databases if necessary.
  5. Restore the site from a backup to reverse any problematic changes.

By following these steps, you should be able to resolve the PHP memory limit error and ensure that your website is running smoothly.

Considering script execution issues, a PHP timeout, for example, may necessitate adjusting timeout rules, as this can be a culprit or common reason for the error. Lastly, if internal efforts fail, seeking assistance from the web hosting provider is key as they can offer insights or solutions to server-side issues that are not within the user’s control.

Navigating Through 503 Server Error Service Unavailability

Person troubleshooting server error issues on a computer

Continuing our exploration of server errors, we now encounter the 503 Service Unavailable error. This error indicates that the website’s server is not ready to handle the request, which may occur due to:

  • being too busy
  • under maintenance
  • high traffic spikes
  • server communication problems
  • resource exhaustion
  • a DDoS attack

These are frequent causes of a 503 error.

Technical difficulties or maintenance work being performed on the server can lead to a 503 Service Unavailable error. Incompatibilities with themes or plugins within a website’s backend may also trigger a 503 error. For users, a 503 Service Unavailable error means they are faced with temporary unavailability of the website due to the server being busy or down.

When a website owner encounters a 503 error, contacting their hosting provider and consulting with a server administrator to assess the status of server-side data and applications for potential problems should be the next course of action.

Differentiating Between Temporary and Permanent Issues

A 503 Service Unavailable status code is indicative of a temporary condition, as stated by the IETF, and is expected to be resolved after a delay. Scheduled maintenance is the most common reason or cause for 503 errors; website owners can confirm this by either being notified in advance, checking server logs, or consulting their hosting provider’s status page.

If a 503 error coincides with unexpected high traffic volumes, it suggests a temporary and unplanned issue rather than a scheduled maintenance event.

Strategies to Resolve the 503 Error

Dealing with the labyrinth of 503 errors demands a suite of focused strategies. Here are some strategies to consider:

  1. Review server logs and enable WP_DEBUG in WordPress to help identify specific causes of a 503 error.
  2. Restart servers and networking equipment to resolve temporary connectivity issues that result in a 503 error.
  3. Flush DNS cache or use a public DNS server like Google Public DNS to fix DNS-related issues that contribute to a 503 error.
How to Promote Products Using Social Media: Effective Digital Marketing Strategies

To troubleshoot and resolve a 503 error, you can try the following steps:

psg digital marketing

  1. Increase server resources or upgrade the hosting plan to handle the load.
  2. Limit or disable the WordPress Heartbeat API if the error is due to resource overuse on the server.
  3. Deactivate plugins and themes to pinpoint compatibility issues that could trigger the error.
  4. Disable a CDN temporarily to determine if it is the cause of the error.

Checking and resetting the Web Application Firewall (WAF) configuration ensures it’s not incorrectly blocking legitimate traffic, which might cause a 503 error.

Server Error: The Perplexity of a 502 Bad Gateway

Network diagram showing server error proxy communication

Our exploration of server errors takes us next to the 502 Bad Gateway error. This is an HTTP status code signaling a communication issue between two servers, most commonly occurring when a gateway server fails to receive a valid response from an upstream server. The 502 bad gateway error indicates server-side problems that can arise due to server overloads, network interruptions, or configuration missteps, affecting the server’s performance.

There are several variants of the 502 error notification including but not limited to ‘502 Service Temporarily Overloaded,’ ‘502 Proxy Error,’ and ‘502 Bad Gateway Nginx,’ each often tied to specific server or proxy setups.

Tracing the Source of a 502 Error

Uncovering the origin of a 502 Bad Gateway error calls for a methodical approach. Server logs provide critical insights that can distinguish if a 502 Bad Gateway error is caused by the server itself or an interfering upstream service. Network monitoring tools are essential for tracking the course of a request to identify at which point the communication fails, resulting in a 502 error.

Developers can trace the source of a 502 error by simulating server requests in a controlled setting and analyzing the response to identify the disruption’s origin.

engaging the top social media agency in singapore

Ensuring Smooth Server-Proxy Communication

Maintaining seamless communication between servers and proxies is pivotal to preventing 502 errors. To maintain smooth server-proxy communication and avoid 502 errors, it’s important to:

  • Ensure correct configuration of proxy servers, VPNs, and firewalls
  • Use a reliable service and connect to a less busy server to mitigate 502 errors caused by overloaded proxy or VPN servers
  • Inspect and verify plugins and themes to prevent 502 errors, as unverified or buggy extensions can provoke server firewall blocks.

Disabling content delivery networks (CDNs) temporarily can determine if they are contributing to 502 errors. Monitoring and adjusting PHP timeout settings, as well as tweaking server configuration file settings like KeepAliveTimeout and RequestReadTimeout, can help prevent 502 errors due to long-running processes.

Maintaining open lines of communication with hosting providers is key for resolving persistent or complex 502 errors that might need server-side intervention.

Troubleshooting Server Error 404 Not Found Dilemmas

404 server error message on a computer screen

The 404 Not Found error is a common yet frustrating experience for both webmasters and users. This HTTP error occurs when trying to access a resource on a web server that doesn’t exist, often due to a broken link or mistyped URL, or if the requested resource or page has been moved or deleted. A 404 Not Found error signifies that the server cannot find anything on the requested location and indicates an attempt to access a non-existing web page.

Improperly managing 404 errors can lead to negative effects on a website’s search engine ranking and deteriorate the user experience.

Preventing 404 Errors with Proper URL Management

Avoiding 404 Not Found errors is vital for upholding a positive user experience and a high search engine ranking. Understanding the cause of 404 errors is essential and can include issues like broken links, deleted pages, or misconfigured redirects.

To reduce 404 errors, ensure that all links on a website lead to the correct URLs and avoid situations where URLs are mistyped. Monitoring and identifying 404 errors can be achieved using tools like Google Search Console, which help in finding broken links and other related issues.

Regularly updating the site, reviewing links, and implementing 301 redirects for deleted or moved pages can help websites maintain valid URLs, make websites preserve SEO value, and prevent 404 errors from occurring.

Customizing 404 Pages for Better User Engagement

While it’s essential to prevent 404 errors, tailoring 404 pages for improved user engagement holds equal importance. Custom 404 pages that help users more easily find what they’re looking for can improve user experience and are becoming more common. A well-designed custom 404 page can enhance the user experience by minimizing frustration and encouraging further exploration of the website.

These custom error pages often have UI-friendly designs that may not even make it immediately apparent to users that they have hit a 404 error. Brand personality and creative elements on custom 404 pages can make the error less frustrating and more memorable for users.

Creating a custom 404 page should include:

  • A helpful message
  • Links to important site pages
  • Promotions or products of interest
  • A call to action
  • A search bar
  • Contact information

Designing a custom 404 error page can provide users with helpful information, such as a search bar, links to popular pages, or access to a site map. Webmasters need to be aware of 404 errors on their site, as a significant number can damage the site’s reputation and search engine ranking. Setting up custom pages for broken links is a recommended practice to counter the ill effects of 404 errors.

Resolving Connection Refused by Host Challenges

Person adjusting firewall settings on a server error network

Next, we’ll address the issues related to connection refusal. To diagnose SSH connection issues, you need to:

  1. Check if the SSH service is running
  2. Ensure the SSH port is open
  3. Verify the SSH daemon is installed
  4. Examine firewall rules

To prevent connection refused errors, verify that the hostname, username, password, and port number being used for the SSH connection are all correct. Troubleshooting a ‘Connection refused’ error when using SSH can include repairing service outages, opening the correct network port, and adjusting firewall settings. If the ‘Connection Refused by Host’ problem persists after troubleshooting, contact the hosting provider for additional assistance.

Checking Network and Authentication Credentials

To avoid ‘Connection refused’ errors, follow these steps:

  1. Ensure the correct SSH credentials are used, including the hostname, username, password, and port. The default SSH port is 22, but for security reasons, it may differ. The correct port information can usually be obtained from the hosting provider or dashboard. Make sure to use valid authentication credentials.
  2. Complex authentication methods, such as NTLM, require meticulous configuration to avoid causing connection refused errors.
  3. Proper setup of authentication configuration files is necessary to prevent credential-related connection refusals.

By following these steps, you can avoid ‘Connection refused’ errors and ensure a smooth SSH connection.

A lack of a valid authentication credentials provider can lead to failed authentications of login credentials, which are a common cause of connection refusal errors as indicated by specific log messages. Incorrect settings in bypassing proxy servers, even when proxies are not used and firewalls are off, can lead to connection refused errors.

How to Find Low Competition Keywords for SEO

get low cost monthly seo packages

Implementing Security Measures Without Hindering Access

Striking a balance between maintaining security and ensuring access is a delicate task. To check the port used for SSH connections, the command grep Port /etc/ssh/sshd_config should be used, making sure that security configurations do not inadvertently close the SSH port preventing legitimate access.

Firewalls must be configured to allow legitimate SSH connections, which involves setting rules to accept requests by adjusting the destination port settings to ACCEPT for secure connectivity and accessibility.

Handling Timeout Errors with Patience

Another commonplace server issue is the 408 timeout error message, which signifies that the server encountered a situation where it did not receive the complete user request within its designated waiting period. If you encounter a 408 error message, the first thing you should do is try reloading the page to see if the error persists. If the issue continues, consider clearing your browser’s cache as it might help resolve the error.

In the event of a 408 timeout error, the server may send a Retry-After header field to suggest an appropriate wait time before attempting the request again.

Recognizing Signs of a Timeout Error

Identifying the signs of a timeout error can enhance your troubleshooting efficacy. An HTTP 408 status code represents ‘Request Timeout’. Signs of a 408 timeout error can include the web page taking too long to load or not loading at all, usually accompanied by a message indicating a timeout.

An HTTP 599 status code represents ‘Network connect timeout error’ and is non-standard.

Optimizing Server Response Times

Significantly reducing timeout errors is possible by optimizing server response times. Here are some steps you can take:

  1. Review application logs to pinpoint web pages or requests causing timeout errors.
  2. Use debugging tools like Query Monitor for WordPress to identify and fix slow server response issues.
  3. Use real-time monitoring tools to effectively identify and address server errors.

By following these steps, you can improve server response times and reduce timeout errors.

Optimizing server-side scripts and code is key to improving their efficiency and response time. Here are some strategies to consider:

  • Caching: Store frequently accessed data to reduce load times and prevent timeout errors related to slow processing.
  • Database optimization: Enhance database response times through streamlined queries and indexing to avoid 408 timeout errors.
  • Continuous testing: Regularly test your server-side code to identify and fix any errors or performance issues.
  • Robust error handling: Implement error handling mechanisms to minimize server-side and client-side errors, ensuring system reliability.

By implementing these strategies, for example, you can optimize your server-side scripts and code for better performance.

website design banner

HTTP Status Code Cheat Sheet of Server Error

Untangling the web of server errors and HTTP protocol status codes can be daunting. This is where an HTTP Status Code Cheat Sheet proves useful. Hypertext transfer protocol HTTP status codes, also known as response codes, are a means for a web server to inform a browser of the status of its request, where 2XX codes indicate successful requests and 4XX to 5XX codes signify various errors.

Client error responses include 400 Bad Request, indicating a corrupt or incorrect request, 405 Method Not Allowed, and 406 Not Acceptable, signaling issues with the request’s content. Server error responses include status codes like 505 HTTP Version Not Supported and 509 Bandwidth Limit Exceeded, which depict server resource constraints or errors. There are also unique non-standard status codes and extensions for more specific error signaling.

Understanding Client vs. Server-Side Codes

Distinguishing between client-side and server-side codes is vital for efficient troubleshooting. A 404 status code indicates a client-side error where a page is not found. User agents should display any included entity to the user when a 4xx client error occurs. On the other hand, 5xx status codes point to server-side issues, distinguishing them from client-side errors.

The 410 error code differs from a 404 by indicating a permanent situation, often intentional, of making a requested resource unavailable.

Leveraging the Cheat Sheet for Efficient Troubleshooting

The cheat sheet can serve as a potent weapon in your troubleshooting toolkit. Understanding HTTP status codes is crucial for determining the origin of an error, with 4xx codes indicating client-side issues and 5xx codes pointing to server-side problems. A status code cheat sheet can be used to quickly understand the meaning behind common codes such as:

  • 200 OK
  • 201 Created
  • 202 Accepted
  • 400 Bad Request
  • 500 Internal Server Error

The cheat sheet file is a valuable tool for debugging and troubleshooting server issues, enabling a methodical approach by referencing the status code returned. By providing a common reference for HTTP status codes, for example, the cheat sheet streamlines the troubleshooting process and aids in communication between team members.


In conclusion, server errors can be daunting, but with the right knowledge and tools, they can be navigated and resolved effectively. From the ambiguous 500 Internal Server Error to the frustrating 404 Not Found error, each error has its own set of causes, troubleshooting methods, and solutions.

The HTTP Status Code Cheat Sheet serves as a handy guide to quickly understand these errors and tackle them methodically. Remember, it’s not about avoiding errors altogether – it’s about mastering the art of troubleshooting!

Frequently Asked Questions

What does server error mean on a website?

A server error on a website indicates a problem with the web server that needs to be fixed to access the website or web application.

What is the code for server error?

The code for a server error is typically in the range of 500 – 599, indicating an issue with the server level that is preventing it from processing the client’s request. This error code is distinct from client error codes (400 – 499), which indicate problems on the client side, such as not being able to find the page or website.

What are client and server errors?

Client errors are indicated by the 4xx class of HTTP status codes, caused by issues with the client’s request or authentication, while server errors are indicated by the 5xx http error class, occurring when the server is unable to fulfill the client’s request due to internal issues or unavailability.

How can I diagnose a 500 Internal Server Error?

To diagnose a 500 Internal Server Error, check the web server’s error logs for details and utilize tools like Trace UI in Apigee Edge or API Monitoring to analyze the cause.

What does a 503 Service Unavailable error mean?

A 503 Service Unavailable error means that the website owner’s server is not ready to handle the request, often due to being too busy or under maintenance.

About the Author

Tom Koh

Tom is the CEO and Principal Consultant of MediaOne, a leading digital marketing agency. He has consulted for MNCs like Canon, Maybank, Capitaland, SingTel, ST Engineering, WWF, Cambridge University, as well as Government organisations like Enterprise Singapore, Ministry of Law, National Galleries, NTUC, e2i, SingHealth. His articles are published and referenced in CNA, Straits Times, MoneyFM, Financial Times, Yahoo! Finance, Hubspot, Zendesk, CIO Advisor.


Search Engine Optimisation (SEO)

Search Engine Marketing (SEM)

Social Media




Most viewed Articles

How to Use SELF in Python

Python, oh Python! It’s a language loved by many for its simplicity and flexibility. One of the key features that sets Python apart is its

Other Similar Articles