Troubleshooting WordPress Multisite Login Issue: Cookies Blocked

One common issue faced by users of WordPress Multisite is the inability to log in to a child site due to cookies being blocked. This problem often arises when utilizing the domain mapping feature, causing login errors to occur. In this blog post, we will explore this issue and provide a solution to resolve it by making a simple update to the wp-config.php file.

Understanding the Problem:

When a custom domain is mapped to a subdomain in WordPress Multisite, users may encounter an error message preventing them from logging in. This error occurs because the necessary cookies are being blocked, hindering the login process.

Solution:

To resolve the “Cookies Blocked” issue and regain the ability to log in to your child site in WordPress Multisite, follow these steps:

1. Access the wp-config.php File:
— Using FTP or a file manager, locate and open the wp-config.php file for your WordPress installation.

2. Add the Configuration Line:
— Within the wp-config.php file, find the section where other configuration constants are defined.
— Add the following line of code just above the line that says “/* That’s all, stop editing! Happy blogging. */”:

define(‘COOKIE_DOMAIN’, false);

3. Save and Upload the Updated File:
— Save the changes to the wp-config.php file.
— If using FTP, upload the updated file back to the server, replacing the existing wp-config.php file.

4. Clear Browser Cache and Cookies:
— Clear your browser’s cache and cookies to ensure any previous cookie settings are removed.

5. Attempt to Log In:
— Open your browser and try logging in to the child site again.
— The cookies blocked issue should now be resolved, allowing you to log in successfully.

Conclusion:

If you encounter the “Cookies Blocked” error while attempting to log in to a child site in WordPress Multisite, it can be frustrating. However, by adding the defined constant ‘COOKIE_DOMAIN’ with a value of false in the wp-config.php file, you can overcome this issue. This simple solution ensures that the necessary cookies are not blocked and restores your ability to log in to the child site. Remember to clear your browser cache and cookies after making the configuration change. With this resolution, you can continue managing your WordPress Multisite installation without login obstacles.