HCL Connections - how fix bad request error when login with Spnego SSO enabled

One of my HCL Customers has reported the following error

Bad Request
Your browser sent a request that this server could not understand.
Size of a request header field exceeds server limit.

when some users was trying to login. 

Connections was not loaded at all, and the HTTP error appeared.
After some investigations we have set this setting on the IBM HTTP server:

LimitRequestFieldSize 12288

in some case , with Spnego SSO enabled a very large cookie could be generated and the default value of this setting ( 8190 bytes ) could not be enough to guarantee the login.

If you like to know more about this , please read the following IBM Technotes:

• Request Header Field Size Exceeds Limit for Web server
• Increasing or decreasing the size of the HTTP Request header field for IBM HTTP Server