Fix the Error Cookies are Blocked due to Unexpected Output

Have you ever encountered the frustrating error message of “Cookies are Blocked due to Unexpected Output” on your WordPress website?

Cookies are blocked

This common problem can prevent you from logging in to the WordPress backend. It can prevent your site from functioning correctly, impacting the user experience and potentially affecting your site’s performance. In this blog post, we’ll dive into the root cause of this issue in the context of WordPress and provide clear, step-by-step instructions on how to fix it.

Understanding the Issue

Let’s first understand the underlying problem. Cookies are small pieces of data that websites store on a user’s computer to track their preferences and enhance their experience. When a user visits your WordPress website, cookies are sent from the server to their browser and stored on their device.

The error “Cookies are blocked due to unexpected output” typically occurs when there’s an issue with the PHP code used to generate a site’s pages. PHP is a server-side scripting language often used to create dynamic web pages, including WordPress sites. When the PHP code generates unexpected output, it can interfere with the proper transmission and storage of cookies, leading to an error message.

Fixing the Error Cookies Are Blocked: A Step-by-Step Guide

To resolve this issue and unblock cookies on your WordPress site, follow the steps below:

Identify the problem source:

Check your server’s error logs or enable PHP error reporting.

Look for “Warning” or “Error” messages in the logs to pinpoint the problematic file(s).

Examine the PHP code:

Open the identified PHP file(s) in a text editor or an Integrated Development Environment (IDE).

Look for instances where data is being sent to the browser before the cookie header is sent, such as “echo,” “print,” or other output functions before the “setcookie()” function.

Remove or modify the problematic code:

Remove the code causing the issue or modify it so that it doesn’t generate output before the cookie header.

Use output buffering by adding the “ob_start()” function at the beginning of your PHP script and “ob_end_flush()” at the end to buffer the output until the script has finished executing.

Test your changes:

Save the PHP file(s) and refresh your WordPress website in your browser.

Check if the error has been resolved and if cookies are no longer blocked.

Test your site using multiple browsers to ensure compatibility across different platforms.

Monitor your site:

Keep an eye on your server’s error logs and your site’s performance to ensure the issue doesn’t resurface.

If the problem persists, investigate other potential causes, such as conflicts with plugins, themes, or issues with your WordPress configuration.


Fixing the blocked cookies error due to unexpected output in WordPress can be challenging, but following the steps outlined in this guide, you should be able to resolve the issue and get your site back on track. Remember to monitor your site regularly and keep your PHP code clean and well-organized to prevent similar issues in the future. Happy coding!

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