I cannot get this to fail.
I was initially testing under Windows 7 and I can install and authenticate both VC for VS2015 2.3 PE and VC Eclipse 2.3 PE without a problem.
I just tested the same thing under Windows 10 and it also worked without a problem. I tested under Windows 10 Enterprise.
What release of Visual Studio 2015 are you using? I tried with the Community Edition and the Enterprise Edition.
Can you try the following?
send an email to me at chris.glazier@microfocus.com
I will then send you an email with a license key for the Visual Studio PE product
Uninstall both products on your system..
Uninstall the Micro Focus License Manager
Navigate to C:\ProgramData\Micro Focus and delete the files lservrc.stn and lservrc.net.
Reinstall VC for Visual Studio 2015
Use the license key that I provide.
Thanks