In addition to this Citrix KNB article I found in some environments it is not enough to set the LimitRequestFieldSize like described, but you can set the value higher. See below the size I tested and validated (24k). A higher value 36k or 48k was not accepted and you will see errors in Citrix Studio for all users.
Symptoms or Error
When Licensing node is selected in Studio: Error You have read only access to the license server.
The Authentication token (HTTP Authorization Request header) is very big and crosses the limit of default request field size the Apache have. Based upon that, we assume that user is part of many Groups.
Add following line in httpd.conf
(C:\Program Files (x86)\Citrix\Licensing\WebServicesForLicensing\Apache\conf)
anywhere below header policies and restart the Web Service for Licensing Service
Add below this line: Header set X-Content-Type-Options nosniff
User is part of many AD Groups.
The original article by Citrix can be found here: https://support.citrix.com/article/CTX232387
Marco Klose works as a Technical Consultant, Architect and CTO focused on Application & Desktop virtualization as well as application delivery with the Citrix product portfolio. He is specialized in Citrix virtualization, Citrix networking and Microsoft products. He has +10 years experience and holds the latest Citrix certifications and is member of the Citrix Partner Expert Council EMEA (PTEC).