Symptoms

We had created a SharePoint page where we had added K2 worklist and K2 form viewer apps to access our K2 forms.
But many users were not able to access this and they would see an error message "Bad Request - Request too Long , Http error 400. The size of request header is too long."

Initially then we found out that the same users were still not able to access the K2 forms using its runtime URL.

Then on investigating we felt that maybe these users have been added to multiple groups in AD and thus request header is very long.
We made some changes in system registry.

HKEY_LOCAL_MACHINESystemCurrentControlSetServicesHTTPParameters

Name Value Type Value Data
MaxFieldLength DWORD 65534
MaxRequestBytes DWORD 16777216


After the change the users were able to access the K2 forms directly from the runtime URL but still not able to access it from SharePoint web part.

 

Diagnoses

This is a known issue with 4.6.8.
 

Resolution

This was eventually resolved by applying a coldfix in all locations specified, then also bringing down the size of the "MaxFieldLength" to 22045 decimal and reducing the size of the "MaxRequestBytes" to a manageable level in the registry - the path is HKEY_LOCAL_MACHINESystemCurrentControlSetServicesHTTPParameters

After testing this issue is resolved.