Documentation

Site-Wide Analysis Tool report fails to open with “400 Bad Request - Request Header Or Cookie Too Large” error

Last update: Wed Feb 11 2026 00:00:00 GMT+0000 (Coordinated Universal Time)

In Adobe Commerce Cloud, the Site-Wide Analysis Tool (SWAT) report fails to open and displays a 400 Bad Request - Request Header Or Cookie Too Large error. This occurs when request headers or cookies exceed the limits set by the server configuration. To fix this, clear cookies and restart your browser.

Description description

Environment

Adobe Commerce on Cloud Infrastructure

Issue/Symptoms

Opening the Site-Wide Analysis Tool report triggers an error message:

h2.400 Bad Request
h4.Request Header Or Cookie Too Large
h5.nginx

Cause

  • Browsers send all cookies for a domain with every request.
  • Using multiple Adobe apps, switching orgs, logging in and out, or accessing both production and staging environments builds up cookies for .adobe.com and related domains.
  • Nginx, the web server used by Site-Wide Analysis Tool and other Adobe apps allows only a limited size for request headers and cookies.
  • If the total size exceeds this limit, the server blocks access, showing a 400 Bad Request - Request Header Or Cookie Too Large error.

Resolution resolution

To resolve the issue, follow these steps:

  1. Open the Site-Wide Analysis Tool (SWAT) site in an incognito or private browsing window. If the report loads successfully, the issue is caused by excessive cookies or headers stored in your browser.

  2. Clear cookies (and optionally cache) for .adobe.com, .magento.com, and .experience.adobe.com in your browser.
    Caution: Clearing cookies will log you out of websites and remove saved preferences and settings.

    • In Chrome, navigate to Settings > Privacy & Security > Cookies and other site data > See all cookies.
    • Search for adobe and magento and remove them.
    • Alternatively, clear all cookies instead of just the cache.
    • If you prefer not to clear all cookies, delete only those for the affected domains. You can also prevent this issue by using a different browser or a dedicated Chrome profile for Adobe admin tasks.

  3. Restart your browser after clearing the cookies.

  4. Try accessing the Site-Wide Analysis Tool URL again.

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