Why are some users intermittently seeing a 404 error

Document ID : KB000102168
Last Modified Date : 15/06/2018
Show Technical Document Details
When we hit the SP initiated url, we are landing to 404 page of login.fcc.
Everything seems to work fine when we are clicking IDP initiated url's. 
SiteMinder Policy Server Version: CA Policy Server R12.52 SP1 CR05 
Policy Server O/S: Win2008 R2 
Web Server: IIS 7.5 Web Server O/S: Win2008 R2 
SiteMinder Web Agent Version: smwa-12.52-sp01-cr08-win32 
Siteminder Option-Pack Version: 
configuration :Partnership SAML2.0 
CA Support Requested Failed Request Trace on IIS

There was No 404 if a shorter URL was submitted: 

The Failed Request Trace showed a 404 httpsubstatus 15 meaning "The Request Filtering module rejected a request with a too long query string" 


Looking at: 

The limit can be changed with the param maxQueryString, which has a default value of 2048. 

I saved the problematic URL into a text file and then looked at the file size = 2,248 bytes 

To increase maxQueryString: 
<requestLimits maxQueryString="<VALUE>"/>