Category: Licensing server

XenApp 7.7 Delivery controller issue – having comms issues getting to the license server?

Recently came across this in my lab where i had 2 sites set up (azure) in opposing continents – one in Europe and in the Americas. The license server i had located in the Americas data center. The delivery controller located in the European data center would from time to time have issues connecting to the license server.

To fix this the FLEXLM_TIMEOUT value must be pushed out to accomodate the latency. To do


i) On the DC,right click start and select Computer > Properties > Advanced system settings > Environment Variables

ii) Configure variable FLEXLM_TIMEOUT to the value 900000

iii) Must reboot the DC to complete the fix

Citrix licensing server tip: if facing a lot of requests here’s how to improve performance

Regularly on large scale citrix implementations the citrix license server might suffer due to the number of requests it’ll receive at peak times. One tip I did come across recently was to review your thread count on the server. This would take 2 forms, one web server thread count and the other server. Defaults for these are normally quite conservative and generally if you are running in a virtual environment you can afford yourself the opportunity to increase these.

Enclosed are the details on how:


Citrix tip: ever need to rebuild your citrix license server? v.careful with hostname

Recently on the discussions a poster bought up they have been encountering issues post citrix license server rebuild.

The user may see the following error when trying to connect:
“Citrix XenApp license acquisition error (-25): Unable to acquire a license from (<server name>) server. Please contact your system administrator or open Event Viewer for more details.”

Sure enough when doing a qfarm load on the systems they were getting a load value of 20000 meaning the servers were unable to acquire a license for the user. Poster made the point their host name was rebuilt with the same name as previous build.

Ultimate fix turned out that not only does the name need to be same but the whether the original name is in capitals or not makes all the difference too. So take note if ever doing a rebuild to check the case sensitivity of the host name of the license server as it won’t provide a license unless its rebuilt as was.