What Is a 401 Error? Most Common Causes and How To Fix It

Encountering a 401 error on your WordPress website can be quite frustrating. Reloading the page might help, but not always. 

So, what’s a 401 Hypertext Transfer Protocol (HTTP) response code, and what does it mean? 

A browser issue may cause this error, but in some rare cases, it could also be a server-side problem. 

The good news is that 401 error codes are often straightforward to fix. In fact, once you identify the source of the error, you may be able to fix it yourself. You could also contact a WordPress expert or your host’s customer support team to resolve the problem. 

Keep reading to learn the causes of 401 errors and how to troubleshoot and prevent them. 

What is a 401 error?

Error 401 is an HTTP status code that indicates your client (or browser) doesn’t have the required permissions to access a particular online resource or webpage. This standard response code may also show when your browser fails to give valid credentials when attempting to access a specific resource.

This error is often a direct result of an issue on the client side. That means there was a bad request from your browser to the server without proper authentication.  

When your browser throws this error, it may result from attempting to access a website using an invalid URL, incorrect username or password or an expired browser cache.

Most times, fixing client-side errors can resolve the issue fast. In other cases, the issue may be on the server side, where the web server blocks valid attempts by the client to access a requested resource. 

This may result from deliberate changes a user made to the server or an accidental failure in the authentication procedure.

When you face this problem, your browser will display an error message. Different platforms give different titles to the 401 error. Here are examples of what you may see:

• 401 authorization required.
• 401 unauthorized error.
• Error 401 unauthorized.
• HTTP error 401 – unauthorized.
• HTTP 401.
• Access denied.

The error code is the most crucial factor here, not the text variations around it. No matter what your browser displays, the error code tells you the problem you’re facing. It’s also the key to your solution. 

Common causes of 401 errors on your WordPress website

Before exploring potential fixes, let’s dive deeper into why your WordPress website may be throwing the 401 error code.

Incorrect URLs

Everyone is guilty of the occasional typo. Typing the wrong URL (Uniform Resource Locator) into the address bar can cause problems, from misdirection to 401 errors. 

What if the URL is correct? Maybe the page has been moved or deleted, and you’re attempting to access an outdated page. 

The server may reject your request in both cases because the client tries to access the resource you want through an unauthorized or invalid path. 

Expired cache and cookies

Your browser uses HTTP cookies to store browser data on your memory, and cookies “remember” your device and browser. Cookies and the browser cache are essential to a fast browsing experience. 

Modern cookies also store your authentication status. That way, you no longer have to log in every time to access a website or social media. Browser cookies keep your online session active while ensuring the server sends you information based on your authorization level.

If your cookies expire or your cache is corrupted or cleared, you may receive a 401 unauthorized error because of improper authentication. 

Firewall and plugin configurations

If you’ve just installed a new plugin or firewall on your WordPress site, attempts to access certain pages may throw 401 errors. 

For instance, some security plugins may take complete control of your website and restrict access to certain pages, even when you have administrator access. 

As the plugin runs diagnostics on your website to optimize it, any login attempts may be perceived as malicious activity. That may cause your website to display a 401 error page.

Also, misconfiguring WordPress plugins can cause 401 errors, especially if you’re handling a new plugin for the first time.

Protected URLs

Access to specific URLs may be strictly controlled or managed at the server level. Only authorized personnel can access these restricted resources. In such a case, attempting to access such a URL from an unauthorized web browser may throw a 401 error.

.htaccess file restrictions

.htaccess files allow you to change the configuration of a directory within a website. Suppose a .htaccess file comes with password protection directives. Unless you have the password, you may encounter a 401 unauthorized access error.

Troubleshooting 401 errors

As we’ve covered above, a 401 error is often a client-side rather than a server-side issue. For that reason, it’s often straightforward to fix. Here are several solutions you may attempt:

Verify the URL

One of the simplest fixes for a 401 error is checking whether the URL used is valid or correct. To secure a website, servers reject attempted access from invalid or incorrect URLs. 

First, ensure the URL is spelled correctly. Check if your target URL has special characters, hyphens and the correct extension. If everything checks out, you should now access the website without problems.

If you still face a 401 error, see if the page address has changed since your last access. It may have been moved or deleted. Go back to the homepage and find the page you want to access. Often, you’ll find the correct link this way. 

Check your login credentials

Another key thing to check is your login details. Attempting to access a website with an incorrect username or password can cause a page to display this error. Ensure you have valid authentication credentials and that the username and password are correctly used.

If you forgot the password, you can attempt to reset or recover it.

Clear and reload the browser cache and cookies

As discussed above, most modern browsers store your authentication status in cookies and the website’s cache. That way, you can always pick up from where you left off.

The cache also helps speed up browsing, as most page files are temporarily stored in your device’s memory to keep your logins active.

Attempting to access a web app with expired cookies often throws a 401 error. 

An easy fix for this is to clear all website cookies for the problem website and refresh the page. You can also clear browsing data and reload the page. This may mean logging in to a new session. 

You can also clear the cache, which deletes all cache files and makes room for new files and logins. That often gets rid of any 401 unauthorized access errors.

The process for clearing cookies differs depending on your browser.

Check for DNS changes

Although rarer than other problems, changes to your domain name server (DNS) may cause 401 errors. DNS records are usually on your device to help it match URLs to their IP addresses. 

If your DNS cache is outdated or expired, you may need to flush it to remove incorrect URLs and IP addresses.

You can flush the DNS cache using the command line and force your device to refresh and authenticate the URLs.

From your Windows command prompt, run the command ipconfig/flushdns. Windows will display a message confirming that the DNS cache has been flushed. 

On a Mac, run the command sudo killall -HUP mDNSResponder.

Deactivate themes and plugins

Installing a new theme or plugin can change the way your website behaves. It can affect the performance of your website and, in some cases, change the PHP, JavaScript or database code. 

If you experience 401 codes on one or multiple pages after installing a new plugin or theme, try deactivating it to see if it resolves the issue. If not, you may have to deactivate and reactivate all your plugins until you find the culprit. 

Rolling back updates also can resolve issues caused by unstable code and eliminate 401 error pages.

Disable passwords on pages

Disabling password protection for some pages on your website can sometimes resolve this error code. You can edit your .htaccess and .htpasswd files, but only if you have intermediate or advanced experience dealing with WordPress files.

To disable password protection:

• Log in to your hosting provider’s control panel and access the file manager.
• Find and open the password-protected directory.
• When enabling password protection, your WordPress website generates a .htaccess file. You may find it in this directory. 
• Create a backup for the file, as you may need it in the future.
• Once done, delete the .htaccess file from the directory. 
• Find the hidden .htpasswd file, create a backup and delete it. 

Check the WWW-Authenticate header response

If none of these troubleshooting tips worked, it might be a deeper server-side issue. 

Your next step is to check your website’s WWW-Authenticate header. This will require administrator access.

When a server generates a 401 response, it sends a WWW-Authenticate header field with at least one challenge to the target resource. This header often has a fixed authentication method a browser must pass to access the chosen page. 

By understanding the response and the required authentication method, you can identify and fix the problem.

To access the WWW-Authenticate header:

1. Open the problematic page in your browser. If you’re using Google Chrome, right-click the page and select inspect. Click Shift + Control + C to open the browser console on Firefox.
2. Select the entry with the 401 error message under the network tab.
3. Click the headers tab. Under the WWW-Authenticate entry in the response headers section, find the server’s authentication method that allows access to the webpage.  

Once you access this section, you can tell where the error is and see how to resolve its authentication problem.

Contact your host

If you’ve tried everything to no avail, you can contact your hosting provider for help. Your host’s tech support team can explore your website and help you troubleshoot 401 and other HTTP errors.

How to prevent future 401 error codes on your website 

Avoiding errors is much better than dealing with them. So, how do you avoid 401 and other HTTP error codes on your website? 

Here are some quick tips:

• Keep your browser updated, which ensures you access websites from an efficient and powerful browser.
• Ensure your server configuration and its functionality are sound. That prevents server errors that may prevent correct page authentication.
• Double-check URLs and login credentials before accessing a password-protected website.
• Clear cookies and your browser cache frequently. Although you may have to log in to websites more often, this prevents potential 401 errors.
• Ensure your WordPress software, themes and plugins are up to date. Using old themes and plugins exposes your website to errors and other vulnerabilities. 

Final thoughts: Bluehost’s guide to fixing and preventing 401 errors

A 401 HTTP response code can be annoying, but you can troubleshoot the issue yourself once you understand how it works. 

You may have an incorrect URL or login credentials — you can correct those issues from your browser. You may also need to clear your browser history, cache and cookies and log back in to your website. If these actions don’t fix the problem, you can try the more involved steps on this list.

Looking for a reliable hosting partner? Check out Bluehost’s WordPress hosting plans and take advantage of automatic core WordPress updates that help keep your website secure and error-free. 

Common questions related to 401 errors