How Labview 2017 Works with a Volume License Server

Hello,
I'm a technician in a high school.
I need to install Labview 2017.
For this I have installed NI Volume license manager 3.1 on our license server.
Then I installed the .lic license file sent by NI Agreements.
Then I install Labview 2017 on the client computer in evaluation mode.
On the client, in the license manager, I add my license server which finds my network licenses.
But when I restart the client again, the customer always asks me to activate.
How do I make the client use the licenses available on the NI license server?
Thank you very much for your help.
cordially