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400 Bad Request Cookie Too Large: What Is It & How To Fix

As internet users, we have all run into different HTTP error codes while searching the web. The “HTTP 400 Bad Request” error is one of the most annoying ones among these. 

This error occurs when the server does not understand the client’s request, which points to an issue with the request itself. There are several possible causes of the HTTP 400 Bad Request Cookie Too Large error.

This post will examine the causes and implications of this issue as well as offer practical solutions to deal with it.

Table of Contents

400 Bad Request Cookie Too Large belongs to the client-related HTTP status codes starting with the number 4xx. The 400 Bad Request: Cookie Too Large error code indicates a request-related issue. Therefore, the server is unable to fully understand and process it. 

HTTP 400 Bad Request Cookie Too Large error


For easy understanding, this error demonstrates that the server cannot process the request because of incorrect request message framing, incorrect request syntax, or misleading request routing.

This error frequently shows when you open a website in your internet browser to look around or do a search. In addition, the problem can be recognized by the brief notice “400 Bad Request, Request Header or Cookie Too Large,” which appears on the displayed screen. 

The website, as well as users, may be significantly impacted by the 400 Bad Request Cookie Too Large issue. Let’s examine how each party is affected by this error:

Users are directly impacted by the Cookie Too Large error, making it more difficult to access material, finish tasks, and customize their experiences on the website. The mistake might cause annoyance and a bad user experience due to session management disruptions and privacy issues.

The followings are detailed information regarding how this error impact user:

  • Disruption to the browsing experience: The website may restrict access to specific websites or features when the 400 Bad Request Cookie Too Large error appears. A partial or constrained surfing experience may result when users cannot access restricted areas or interactive features.
400 Bad Request Cookie Too Large error impacts the user browsing experience


  • Sessions interrupted: Cookies are essential for preserving user sessions across different sites and visits. The cookie size may be excessive, resulting in improper session data storage, numerous session interruptions, and users logging in repeatedly.
  • Submissions of incomplete forms: Users might not be able to carry out crucial online tasks, such as completing contact forms, signing up for newsletters, or placing orders if the mistake happens during form submissions. This may be upsetting and interfere with their ability to use the website efficiently.
  • Failure to maintain login: The issue may prevent users from remaining logged in on websites that employ user accounts. Because of this, they will have to enter their login information more frequently, which will be annoying and might reduce user engagement.
  • Loss of individuality: Websites use cookies to customize user experiences. Thus, when a 400 Bad Request Cookie Too Large error appears, it will disable the storage of relevant cookie data. Then, users might not receive personalized content, recommendations, or settings they had previously chosen.
  • Lost data or corrupted cookies: This error may cause users to lose important data if a website heavily depends on cookies to store user preferences, settings, or data. Owing to this, user experience may be affected, and users may need to reconfigure their preferences.
  • Negative user experience: If the website frequently runs into the 400 Bad Request Cookie Too Large error, it may cause a negative user experience. Users may be less satisfied and less likely to return to the website in the future if they keep experiencing the same error
  • Privacy and security issues: When a website sets up huge cookies with excessive amounts of sensitive or personal data, a “400 Bad Request: Cookie Too Large” error can appear. As a result, users may get concerned about their security and privacy.

The “400 Bad Request: Cookie Too Large” error can have serious adverse impacts on a website’s user experience, engagement, income, SEO performance, and brand reputation.

Below are several significant impacts of this error on the website:

  • Loss of user experience: The 400 Bad Request Cookie Too Large issue severely affects user experience and may obstruct browsing or prohibit access to particular pages or features. As a result, users may become frustrated and dissatisfied, possibly leaving this website and looking for alternatives.
  • Conversion rates affect: The Cookie Too Large error can immediately affect income generation for e-commerce websites or other types of conversion. When users cannot finish transactions or perform required actions, they will likely give up on planned tasks, leading to missed sales chances.
  • Consequences of Search Engine Optimization (SEO): Search engine rankings heavily depend on user experience. Thus, the website’s SEO performance may be significantly impacted by greater bounce rates and shorter dwell periods on a website that frequently encounters this mistake.

Read more: 12 Ways to Optimize your SEO Ranking in 2023

  • Credibility and trust: The reputation of the website’s brand may suffer if the issue continues. Customers can think the website is not well-maintained, not professional, or doesn’t pay enough attention to technical issues. Online reviews and negative word-of-mouth could further damage credibility.
  • Decreased user engagement: If users face the problem and cannot view the content or take any actions, their engagement with the website may decrease. Also, the frequency of this issue might result in higher bounce rates and shorter visits, which harm important user engagement metrics.
  • Challenges with analytics and tracking: Incorrect or partial data gathering may result from the issue interfering with analytics and tracking tools. This limits the website’s ability to comprehend user behavior, make data-driven decisions, and enhance the user experience.
  • Possible security issues: The Cookie Too Large error may also be caused by a security risk. Large cookies can potentially have too much sensitive user data, raising concerns about data handling procedures and potential weaknesses.
400 Bad Request Cookie Too Large error causes security issues


  • Increased support and troubleshooting overhead: Users having trouble with the website might contact customer service more frequently. The support team’s effort and overhead may increase due to responding to these support requests, taking time away from other duties.

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When a cookie’s size exceeds the server’s maximum allowable limit, the 400 Bad Request Cookie Too Large error occurs. This error has several typical causes, including the following:

  • Problems with the server – Nginx web server: It is a problem with a certain server and the linked websites. The issue is shown on the Nginx server-typically hosted websites. This prevents browser cookies from exceeding a specific size, so the server declines to display the website.  

Read more: 400 Bad Request Nginx: What Is It & 6 Ways To Fix

  • Too many or corrupted cookies: Websites that rely heavily on cookies or unintentionally store a lot of data in cookies run the risk of exceeding the browser’s size limit.
  • A lot of data is stored in cookies: Cookies are designed to store discrete information, such as user preferences or session data. Cookies can easily exceed the size limit of a browser if a website opts to store a great deal of data there rather than using another storage method.
HTTP 400 Bad Request Cookie Too Large error


  • Attacks of cross-site scripting (XSS): Through cross-site scripting (XSS) attacks, attackers may occasionally attempt to insert dangerous code into cookies. These malicious programs can make cookies larger, leading to the Cookie Too Large error.
  • Issues with browser compatibility: The allowed cookie size varies between browsers. Some users may receive the 400 Bad Request Cookie Too Large error message because a cookie that works in one browser may go above the limit in another.
  • Third-party cookies: Websites frequently use third-party services for tracking, analytics, or advertising. These third-party services may increase the size of cookies and cause Cookie Too Large errors if they set cookies with huge data payloads.
  • Limitations of websites: Some websites limit the amount of data that can be requested at once. This is frequently brought on by worries about security or restrictions with their network architecture.
  • Policies of cookie security: Users of certain browsers can change their cookie settings, including setting size restrictions. This error can appear even if the website’s cookies are under the default limit if a user manually decreases the cookie size limit in their browser settings.
  • Unproductive cookie management: The error may result from improper cookie handling on the website. The website, for instance, can establish cookies without adequately verifying their size or expiration dates, resulting in larger cookies than allowed.
  • Browser extensions: Because they have the potential to alter, produce, or interfere with cookies, setting browser extensions can result in the Cookie Too Large issue.

Several actions must be taken to optimize cookie usage and ensure cookies stay below the browser’s size limit to resolve the 400 Bad Request Cookie Too Large issue. An instruction manual for fixing the issue is provided below:

Clear Cookies Or The Browser Cache

Client-side site data, content, and session history are stored in browser cookies and cache to enhance the user browsing experience. By doing so, fewer requests to the server are made, and customized browsing is made possible.

Cookies, however, could expire after a while. Additionally, if the web browser provides excessively big cookie data, the website’s cookies and cache may become corrupted, leading to a 400 Bad Request Cookie Too Large error.

Remember that clearing your browser’s cache and cookies will reset your settings and log you out of previously visited websites. Furthermore, it will take longer for websites to load because the browser will have to retrieve previously cached content.

Use Incognito (Or Private) Browsing Mode

A temporary fix for the 400 Bad Request Cookie Too Large issue is to use the Incognito (or Private) browsing mode. Any cookies saved from earlier browsing sessions are unavailable when you open a new Incognito window in your web browser.

However, this method cannot permanently fix the Cookie Too Large error. Thus, if the error continues even in incognito mode or reappears after deleting cookies and cache, it suggests that there are further underlying problems behind the error you should take a look at.

Contact The Website Support Staff

The support staff or administrators of the website may provide helpful advice and insight into the particular problem affecting their site. 

By contacting the website’s support staff, you can improve your chances of resolving the 400 Bad Request Cookie Too Large error and assist the site’s administrators in identifying and correcting any potential problems with their site’s cookie management. 

Contact website support staff to ask for help fixing a Cookie Too Large error


It is important to keep in mind that effective communication with the support staff can result in a quicker resolution and a better surfing experience for all customers.

Verify The Domain Address Once More

A wrong URL can result in a Cookie Too Large error, which may include incorrect syntax, an illegal character, and a typographical error.

Because it is simple to write a URL incorrectly, double-check the spelling of the domain name. Consider special symbols like a hyphen (-) or percentage character (%) if the URL comprises a directory path, file name, or query string.

You can use a reliable tool to decode and reencode the URL to ensure it is right if you receive a 400 Bad Request Cookie Too Large error due to an incorrect URL.

Disable Or Restrict Third-Party Cookies

In contrast to the website you are currently visiting, third-party websites or services may set their cookies on your device. These cookies may increase the overall cookie size and result in an error if the browser’s size limit is exceeded. 

Consider disabling or reducing the use of third-party cookies whenever possible if the mistake is brought on by the establishment of large cookies by third-party services. You can consider substitutions that use local storage within the browser or server-side storage.

Be aware that: This approach may impact some website features, particularly those that heavily depend on third-party services for monitoring or personalization.

Switch To A Different Browser

You can switch to the website on several browsers to confirm cookie compatibility. Testing will help find inconsistencies because different browsers have varying cookie size restrictions. 

Utilizing a different browser can narrow down the issue and establish whether the mistake is particular to one browser’s cookie handling or a more widespread problem. 

Verify The Settings For Your Load Balancer Or Proxy

When dealing with the 400 Bad Request Cookie Too Large error in a distributed web environment involving numerous servers, it is crucial to check the proxy or load balancer setups. Sometimes proxies and load balancers might obstruct cookie management and result in problems with cookie size limitations.

Remember that modifying the specifications of your load balancer and proxy can significantly affect how well your website performs along with how visitors interact with it. Before implementing modifications to the production system, always exercise caution when making settings adjustments and properly test them in a safe environment. 

Note: The Cookie Too Large error can be successfully fixed with knowledgeable system administrators or network experts.

Turn Off Browser Extensions

Another troubleshooting technique to take into account while attempting to fix the Cookie Too Large error is disabling browser extensions. Some browser extensions have the potential to cause issues by interfering with cookie management or increasing cookie size.

If the problem still exists after disabling the extensions, try refreshing the website where you received the 400 Bad Request Cookie Too Large message. If the error disappears, one or more extensions are the issue’s root. After that, you can try turning on each extension to find out which one is the problem.

Note that: Certain extensions, particularly those about security or cookie management, may impact the functioning and security of websites. If you discover that a particular extension causes the problem, you have two options: disable the extension while using the website or contact the extension’s creator for support or updates.

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It can be frustrating to receive the HTTP 400 Bad Request Cookie Too Large error message, but if you can identify the underlying issue and take the necessary actions, you can resume seamless internet surfing. 

You can solve the problem and have an error-free online experience by using the methods for fixing it described in this blog post. Remember to frequently clear your cookies, keep your browser up to date, and contact website management if the issue continues.

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Hello, I'm the Chief Technology Officer of Mageplaza, and I am thrilled to share my story with you. My deep love and passion for technology have fueled my journey as a professional coder and an ultra-marathon runner. Over the past decade, I have accumulated extensive experience and honed my expertise in PHP development.
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