Error: HTTP 400 Bad Request: Request Header Too Long

Symptom

When attempting to use SSO for the Published Reports web console (port 8082), you encounter the following error:

HTTP 400 Bad Request (Request Header too long) responses to HTTP requests

Cause

This issue may occur if the user is a member of many Active Directory user groups.

The HTTP request to the server contains the Kerberos token in the WWW-Authenticate header. The header size increases together with the number of user groups. If the HTTP header or packet size increases past the limits configured on the server, the server may reject the request and send an error message as the response.

Resolution

To resolve this error, follow the steps below:

1. For IIS 6.0 and later, the MaxFieldLength and MaxRequestBytes registry keys are located at the following subkey:

   • HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters

2. Set the key values as shown in the following table:

   Name	Value Type	Value Data
   MaxFieldLength	DWORD	(4/3 * T bytes) + 200
   MaxRequestBytes	DWORD	(4/3 * T bytes) + 200

3. You can also set the registry keys to their maximum values, as shown in the table below. Consider all potential security ramifications before making any changes to the registry settings:

   Name	Value Type	Value Data
   MaxFieldLength	DWORD	65536 (Decimal) or 10000 (Hexadecimal)
   MaxRequestBytes	DWORD	16777216 (Decimal) or 1000000 (Hexadecimal)

For detailed information on this error message, refer to the full Microsoft documentation: Troubleshooting HTTP 400 Bad Request Responses — Microsoft 🤥.

Related Article

• Troubleshooting HTTP 400 Bad Request Responses — Microsoft 🤥