A “501 Not Implemented” error occurs when a website you visit lacks the functionality to retrieve or show information that your web browser has requested. A 501 error is one of several HTTP status codes your browser might display.

Your browser will display server error responses (or HTTP status codes) with numbers ranging from 500–599. These error codes have different means and different solutions. This article will show you how to fix the “501 Not Implemented” error on several devices and operating systems.

501 Not Implemented: What Does It Mean?

When you visit a website, your browser sends a request to the site’s server. If everything goes right, the website supplies the requested data. This response could be text, images, files, and so on. If there’s a problem with the web server and it fails to handle your request, your browser will display the “501 Not Implemented” error.

What this error means is that the server lacks the functionality to fulfill or “implement” your browser’s request. Even more precisely, the server fails to recognize the HTTP request method used by the browser.

Most of the time, a 501 error is caused by a problem with the website’s server. However, on rare occasions, problems with your web browser and network settings could also trigger the error. Whatever the cause, the troubleshooting tricks listed below could fix the issue.

1. Reload or Refresh the Page

The “501 Not Implemented” error is sometimes temporary, perhaps due to server overload or traffic surge. If the site administrator fixes the problem quickly, reloading the webpage may resolve the error. Press F5 or Ctrl + R (Command + R on Mac) on your keyboard to refresh the affected webpage. Do that as many times as you can. Proceed to the next troubleshooting solution if the error persists after refreshing the page multiple times.

2. Check the Website’s Server Status

Site monitoring tools (like DownDetector or IsItDownRightNow) provide real-time reports of server outages for websites and online services. Perform a server status check on the website displaying the “501 error” using the tools mentioned above.

If the tools report a server downtime or outage, you’ll need to wait for the website to come back online. Contact the website administrator if the error persists after several hours or days.

3. Try a Different Browser

Visiting the website in a different browser can help determine if the problem stems from your browser, device, or the website’s servers.

If other web browsers load the website properly, that rules out the possibility of a server-side error. In that case, clearing your browser’s cache might resolve the problem.

4. Clear Your Browser Cache

Cached web data is supposed to help your browser load web pages faster. However, your browser may encounter issues loading web pages if its cache data becomes corrupt or outdated.

If the 501 error response code is specific to a particular browser, clear the browser’s cache and reload the webpage. Follow the steps below to clear cached web data in Chrome, Firefox, Safari, and Microsoft Edge.

Clear Browser Cache in Google Chrome

  • Open Chrome, paste chrome://settings/clearBrowserData in the address bar, and press Enter/Return.Head to the “Advanced” tab, set the “Time range” to All time, check Cached images and files, and select Clear data.

Clear Browser Cache in Microsoft Edge

Open a new browser tab, paste edge://settings/clearBrowserData in the address bar, and press Enter or Return on the keyboard. Check Cached images and files and select Clear now.

Clear Browser Cache in Mozilla Firefox

Open a new browser tab, paste about:preferences#privacy in the address bar, and press Enter/Return on the keyboard. Select Clear Data in the “Cookies and Site Data” section, check Cached Web Content and select Clear.

Clear Browser Cache in Safari

Open Safari, select Safari on the menu bar, and select Preferences. Head to the Privacy tab, select Manage Website Data, choose Remove All, and select Remove on the confirmation.

5. Disable Proxy Server

Your computer’s proxy settings affect how your web browser(s) load certain websites. If you’re surfing the web via a proxy server, disable it (temporarily) and check if that stops the 501 error code.

By default, many web browsers use your computer’s proxy settings. So, unless you set up a manual/custom proxy configuration in your browser, disabling proxy at the system level should do the trick.

In Windows, go to Settings > Network & internet > Proxy and any manual or automatic proxy setup on the page.

To disable proxy settings in macOS, head to System Preferences > Network > Advanced > Proxies, and uncheck all proxy or HTTP protocols. Select OK to save the changes and reload the website in your browser.

On a Chromebook, go to Settings > Network > Wi-Fi or Ethernet and select the active network. Afterward, expand the Proxy drop-down menu, and set the “Connection type” to Direct internet connection.

6. Perform a Virus Scan

Malware infection on your computer can affect information exchange between your computer and the website’s servers. Before performing a malware scan, try visiting the webpage on another computer. If other devices load the webpage, the 501 error on your computer could be due to malware infection.

If you’re using a Windows PC, open Windows Defender (or Windows Security) and run a full scan of all files and running programs. Leave your browser open while you run the malware scan. You can also use third-party apps to diagnose security threats and fix malware infections in Windows.

For non-Windows users, check out some antivirus options for Mac, free antivirus programs for Linux, and antimalware solutions for Chromebook.

Troubleshooting Tips For Website Administrators

Expired server software or subscription could land your site visitors on an HTTP 501 error page, as will incorrect NGINX configuration in your server settings. If you own or manage the website displaying the 501 error, ensure your hosting bills are paid. Additionally, make sure your web application is up-to-date. 

Failure to fix this error in time could negatively impact your site’s SEO ranking. Contact your hosting provider for assistance if you have no technical knowledge of troubleshooting server-related issues on the backend.