Citrix License Server - proxy configuration issue
Article ID: CTX696173
Updated On:
Description
Administrator is not able to configure a proxy using Citrix Licensing Manager.
Attempt to add a proxy server fails with the error: The proxy server isn't reachable. Try again.
Ctxlcs.log file located in C:\Program Files (x86)\Citrix\Licensing\WebServicesForLicensing\Logs shows the 'invalid proxy' error.
31/01/2026 10:54:23.145 [Error] : LCSOperations::setProxy : lcsoperation.cpp : 616 : while adding proxy adreess: http://proxy_address failed with following error
ERROR_INVALID_PROXYPowerShell: Test-NetConnection proxyaddress -Port proxy_port shows that connection is possible.
Network trace captured on the license server shows that:
- There is an attempt to contact specific Citrix URLs
- Destination IP is correct, and this is a proxy server address
- The response is coming back from the proxy server
- Authentication is required.
Cause
Proxy server requires authentication.
From Citrix documentation:
Citrix Licensing components requiring outward bound web communications can inherit network proxy settings using Windows automatic proxy detection. We do not support authenticated proxies. For more information about Windows automatic proxy detection, see WinHTTP AutoProxy Functions.
Resolution
Check connectivity to the proxy server using PowerShell: Test-NetConnection proxyaddress -Port proxy_port.
Check errors logged in Ctxlcs.log.
Capture and check a network trace using a preferred tool (in this example: Wireshark), filter HTTP traffic.
Disable authentication requirement on the proxy server for the License Server Machine.
Issue/Introduction
This article explains what data is useful for proxy configuration troubleshooting and shows one of the common issues.
Additional Information
