What is the 503 Service Unavailable Error?

March 23, 2022


The HTTP 503 service unavailable error code indicates a website is temporarily unavailable. Whether you're a website visitor or an administrator, the 503 page is bothersome.

Although the error suggests a server-side issue, there are some possible solutions for both visitors and web admins.

This guide explains what the 503 error is and how to troubleshoot it.

What is The 503 Service Unavailable Error


  • A stable internet connection.
  • Access to the webserver resources (for web administrators).

What Is 503 Service Unavailable?

The 503 service unavailable error is an HTTP status code response. The code indicates the webserver is temporarily unable to process the request.

The two most common reasons for the 503 error are:

1. The server is overwhelmed with requests.

2. The server is undergoing maintenance.

This is a server-side error, meaning the problem is on the website’s end.

Note: Every error code carries a different meaning. Learn about the 403 forbidden or the 500 internal server error.

503 Error Variations

The error is customizable by web developers and varies between different web servers. The issue may look like any of the following:

  • 503 Error
  • 503 Service Temporarily Unavailable
  • Error 503 Service Unavailable
  • Error 503 Backend Fetch Failed
  • 503 Service Unavailable
  • HTTP Error 503
  • HTTP 503
  • HTTP/1.1 Service Unavailable

The error page contents and names differ depending on the website setup.

How to Troubleshoot the 503 Service Unavailable as a Visitor

Although the error is on the server's end, there are still some steps to take to troubleshoot the 503 service unavailable error on your end. Try some of the steps below and see if the issue resolves.

Refresh The Website

The quickest way to troubleshoot the 503 service unavailable error is to try and refresh the web page. Typically, the error is temporary, and the issue resolves quickly.

Warning: If the error happens on a payment page, refreshing can invoke a second charge. Double check if the payment already went through before committing to this option.

Refresh the page by pressing the reload button in the browser or the F5 key.

refresh button browser

For hard refresh, use the Control + F5 keys. On MacOS, use Command + Shift + R and Command + Option + R for Safari.

Check If the Site Is Down for Other People

Check whether the website is down for everyone else. To do so, visit one of the following websites and enter the website link where the error shows up:

website status up

If the result shows the website is up, the problem is local. Try troubleshooting DNS issues as an alternative.

Restart Your Networking Devices

Temporary problems with networking devices, such as the router or modem, sometimes result in the 503 error.

If the website is up and the connection still doesn't work, a simple restart of the network equipment and the machine can reset everything back to normal.

Visit the Website Later

If all else fails, try visiting the website later. Since the 503 error is often due to a spike in website traffic, leaving the website helps decrease the load. As more users disconnect, the potential for a successful connection increases.

How to Troubleshoot the 503 Service Unavailable Error as a Website Administrator

The 503 service unavailable error is tricky to pinpoint. The following sections each provide a possible solution.

Retry the web page after each method. Check if the problem is gone before moving on to the next solution.

Restart The Server

Restarting the server is the quickest way to refresh traffic overload. By doing so, the website server chain breaks, which in turn frees your website from congestion.

If the website runs on multiple servers, restart each server to see if the problem persists.

Check for Server Maintenance

Server maintenance is often a cause for the 503 error page. If possible, check the server's admin settings to see the maintenance schedule.

Additionally, check if there's an option to disable automatic updates. Maintain the server regularly and take complete control over the maintenance schedule.

Check Firewall

A firewall monitors all network traffic and helps decide which requests are malicious to stop potentially unwanted visitors. An incorrect configuration in the firewall prevents valid traffic, leading to the 503 service unavailable error.

Check the firewall configuration for your web page. If the firewall service is automatic, see whether you can create a better solution.

For example, set up a firewall on a small BMC server instance for better traffic control and improved network security.

Check Server-Side Logs

Every web application keeps server-side logs. Two log types are essential for troubleshooting the 503 service unavailable error:

1. Application logs keep the application history, such as requests, connections, and database results. Check for any anomalies in the code or results to see if anything is causing the error.

2. Server logs track hardware details, such as the status and health of all services and general server monitoring. The log location differs based on the web application's configuration.

Check Website Plugins

A common cause for the 503 service unavailable error is plugin compatibility. The quickest way to check whether plugins are the underlying cause, disable all plugins and check if the error is gone.

In WordPress, the error disables access to the admin area. Disable the plugins by accessing the files through an FTP client, such as FileZilla, and rename the plugins folder.

If the issue resolves, the problem is with one of the plugins. Rename the plugins folder back to the original name and disable plugins one by one, checking after each to pinpoint the issue.

Check Website Theme

Another issue that causes the service unavailable error in WordPress is the website theme. To check whether the theme is causing problems, do one of the following:

  • Access the WordPress database and disable the theme through phpMyAdmin. Locate the template option name and change to a default theme.
wordpress phpmyadmin template name
  • Reinstall the theme.
  • Revert to the most recent backup.

Check CDN

The Content Delivery Network (CDN) helps deliver content to websites. A problem with the CDN indicates the 503 error is not on the website itself.

Every CDN has an option to disable or pause the service temporarily. Turn off the CDN and see if the website is available. If the problem is not the CDN, turn the service back on.

Increase Server’s Resources

After all the suggestions, if the 503 error persists, the problem is the webserver resources. Upgrade to a better hosting plan to handle the traffic increase.

Contact the webserver hosting support and explain the steps taken to resolve the issue before committing to an upgrade.


After following the steps from this tutorial, you know what the 503 service unavailable error is and how to troubleshoot the issue.

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Milica Dancuk
Milica Dancuk is a technical writer at phoenixNAP with a passion for programming. With a background in Electrical Engineering and Computing, coupled with her teaching experience, she excels at simplifying complex technical concepts in her writing.
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