When you click on a website and the page doesn’t show anything except a “400 Bad Request” title on an otherwise blank page, this means that the site isn’t properly loading. This error can occur if a server doesn’t process or understand a request that a browser sends.

HTTP response codes that start in the 400 range usually indicate that something’s wrong on the client’s side. However, there are many potential causes of this error. For every minute that your website is down because of this error, more and more visitors will see it.

Depending on your brand image, this type of error could damage your reputation. The key to maintaining customer loyalty is to minimize downtime and provide site visitors with a stellar experience. The following guide explores the 400 error and describes how you can resolve it.

What is a 400 Bad Request Error?

A bad request error is one of the many HTTP status codes that can be displayed when something goes wrong with a website. HTTP status codes are server responses to requests from browsers. When a user visits your website, their browser submits a request to your site’s server. The server responds by sending a three-digit code, which should allow the user to enter without issue.

The purpose of status codes is to allow the browser and the server to communicate about whether things are okay, spotty, or bad. By understanding what status codes mean, you can effectively diagnose the errors on your site, which should help you reduce downtime.

The bad request error says that your page isn’t found. Either the site or page can’t be reached. If a page doesn’t exist, this error can occur. However, a 400 error doesn’t determine if the page is missing temporarily or permanently.

Your site should automatically have some 400 error codes. When a user incorrectly types your URL, they should reach this page. If the 301 redirect error constantly occurred and sent users to your homepage, they wouldn’t understand that the initial address they entered was inaccurate. These errors usually indicate that the problem is on the client’s side.

Common Causes of 400 Bad Request Errors

There are many possible causes associated with these errors, which can be separated into categories like client-side, server-side, and network issues.

Client-Side Issues

It’s possible for something to be wrong on the user’s end. The types of client-side issues that can cause these errors include everything from deceptive request routing to malformed request syntax. Incorrect syntax can involve typos and poor application logic that cause the request by the user to be incomprehensible to the server.

The issue may also be caused by invalid request message framing. Data corruption or software bugs can cause deviations that stop requests from being processed. If the user includes an invalid character in the URL, a 400 error could occur. The client-side issue could involve deceptive request routing through networks, which can create problems with communication between the client and server.

Server-Side Issues

Even if the quality of the server is well-maintained, multiple issues can lead to this error. For example, there may be problems with the configuration of your website’s server.

It’s possible that the server is waiting for additional information from the user that they didn’t send. The user can’t do anything to correct this problem. While the user is making a valid request, the server is responding incorrectly.

Network Issues

The 400 error can also show up because of network issues. For example, the issue could be caused by DNS lookup errors. DNS refers to Domain Name System. This system translates domain names directly into IP addresses.

These records are stored in the operating system’s DNS cache. If a website’s IP address changes, these records can become outdated. The user may also have network issues because of a poor internet connection.

How to Diagnose a 400 Bad Request Error

There are numerous tools that can help you diagnose this issue, which include browser developer tools and online HTTP header analyzers.

Client-Side Diagnosis

To determine if the error is based on a client-side issue, check the URL for any typing mistakes. A single misspelled word can lead to this error. You can also clear the browser cache and cookies.

The cache stores files like images and text on the client’s side to expedite page loading. Cookies track login details and session history. Over time, the cookies and cache can become old and outdated, which might cause this request to come up. Clear the cache and cookies to fix the error.

You can also examine request headers and payload on the client side to make sure cookies are being properly sent and received. Check to determine if the proper HTTP version is being used.

Server-Side Diagnosis

The 400 error you get could come from your own website because of invalid HTTP headers or poor server configurations. The first step in diagnosing server-side issues involves reviewing server logs to validate configurations. These logs can inform you of what your website did, which pages were requested, and the database results that occurred. These logs can give you information about the status and health of the services that are connected to it. Your website may be configured incorrectly if it’s a custom one.

Tools for Diagnosis

There are numerous tools that can diagnose bad request errors. For example, some browsers offer developer tools. If you use Chrome DevTools, you can debug 400 errors and other HTTP issues. WordPress also offers a debug mode.

Consider using HTTP header analyzers as well. You can access these tools online, many of which are available for free. An example of an HTTP header analyzer is Security Headers. Once you enter your site’s address on the website, you can scan it for header errors.

To monitor your website’s server, consider the following tools:

• Anturis
• NinjaOne
• CollectD
• New Relic
• LogicMonitor

Fixing a 400 Bad Request Error

Once the reason for the error is identified, you can start fixing it.

Client-Side Solutions

The initial thing to do when resolving a client-side issue is to correct the URL. Check the spelling and syntax before clicking “Enter”. You can also refresh or reload the page to see if the 400 error returns. As mentioned previously, clearing the cache and cookies may allow you to resolve this issue. The process differs with each web browser. When using the Firefox browser, take these steps:

• 1. Select the three horizontal lines in your browser
• 2. Click “Settings”
• 3. Select the “Privacy & Security” tab
• 4. Choose “Clear Data” under “Cookies and Site Data”

If you have any browser extensions installed, disable them. In Firefox, you can disable extensions by clicking the puzzle piece. The next step involves selecting “Manage Extensions”. From here, you can disable any extension that’s currently running. This process is similar among all browsers.

Server-Side Solutions

On the server side, you might be tasked with updating configurations. This can be a complex process depending on the servers you’re using. With Azure, you can use the Microsoft configuration settings guide to make the necessary updates.

It’s also crucial that requests are handled properly when users attempt to enter your website. Every request that’s sent to your site must be validated and authorized. Authorization involves making sure that the user has the permissions needed to perform the action they’re attempting to take. You may need to format your site’s responses to ensure requests are handled correctly.

If the issue is caused by bad server-side code or invalid headers, analyze them to find potential errors. You can fix this issue by inputting the right code.

Network Solutions

You can correct network issues by updating DNS settings or taking steps to improve internet connection stability. In Windows, you can check and update DNS settings by clicking the Win key to show the Start menu. Input “Settings” into the box to bring up the settings menu.

Choose the Network & Internet option to find your network’s name. You should then select the “Properties” button. The DNS server you’re using will be shown in the window beside IPv4 DNS Servers. Consider changing to the preferred DNS server of 8.8.8.8 or 8.8.4.4.

Test the stability of your connection by looking at the internet insignia on the Windows taskbar. If the signal is weak, consider disconnecting other devices from your internet, which can include everything from smart TVs to your phone. If this suggestion doesn’t work, turn your modem off and on.

Preventing Future 400 Bad Request Errors

When users visit your website and incorrectly see 400 errors, it will be your responsibility to identify the cause and fix the issue. You can avoid this hassle by preventing these errors in the first place.

Best Practices for Developers

The developers on your team should know how to validate and sanitize input data. Validation involves checking the input to ensure it meets certain criteria. Sanitization alters the input to ascertain its validity.

Your website should be set up to handle errors and respond promptly to user feedback. When a user informs you of an error, provide them with actionable solutions. It’s possible that the error is on their end. Check your server software regularly to make sure everything’s up to date.

Best Practices for Users

When using a website, make sure that you input the correct URL, keep your browser updated, and avoid browser extensions that interfere with requests. Most browsers remind you when updates are needed.

Conclusion

When a user tries to enter your website and receives a 400 bad request error, they could leave and never return. Understanding what this error means and how to diagnose it allows you to fix the issue yourself or provide your customers with effective solutions. If it’s a server-side issue, you might need to update configurations or correct bad coding. You can prevent 400 errors by making sure your team of developers maintains best practices. Minimizing web errors on your end can help keep your customers satisfied.