500: Server Error [20-0004]

when you get below mentioned error

500: Server Error [20-0004]

This is siteminder Web Agent error, If your website is SSO protected, then it might have Siteminder ISAPI issue with initializing.

Check Event and SSO logs.

Thread: HTTP Error 400 – Bad Request – Request Too Long

When you get error given below while browsing application hosted on IIS 6 or 7.0.

Error

Bad Request – Request Too Long

—————————————–

HTTP Error 400. The size of the request headers is too long.

400 - Bad Request

Solution :

Create DWORD keys in register @ HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters”

Name Value
MaxFieldLength 32767(Decimal)
MaxRequestBytes 16777216(Decimal)

and reboot the server as http.sys will not take these parameters in effect until you reboot the server.

Related Article:

http://support.microsoft.com/kb/820129/en-us