Citrix Single Sign-On Service Key Management Module could not be contacted

When starting the Citrix SSO agent there is the following error message:

The Citrix Single Sign-On Service Key Management Module could not be contacted

The reason for the failed start of the Citrix Single Sign-On-Service can be the excessive size of the user token. The token size  increases proportionately by the number of group memberships of a user object in the Active Directory. Because of the excessive token size the SSO service cannot resolve the permissions of the user object.

Adjust the token size to start the Citrix Single Sign-On service

The basis for the Citrix SSO service is an Apache server. The server filesare not located in the installation directory of the Citrix password manager, but you can find it here:

„%CommonProgramFiles(x86)% \Citrix\XTE“ for 64 bit systems or
„%CommonProgramFiles% \Citrix\XTE“ for 32 bit systems.

1. In the XTE directory you can find the sub-directory “conf”, where the file “httpd.conf” is located.
2. Open the “httpd.conf”with a plain text editor.
3. Search the parameter “LimitRequestFieldsize”
4. Increase it to “16384”
5. Save the file and restart the SSO service.