What are all the possibilities of getting "Virtual clients are not supported" while activating a license on a Virtual machine?
There can be many reasons for activation failure with this error however always good to check the following points for possible solutions
1. First check the license model policy under the Virtualization policy setting for Allowing activation on a Virtual machine set No then update to Yes. By default Yes,
2. Make sure VM Detection enabled in the client kit, for example from the demo .NET kit
3. Also check system -> configure -> Embedded Devices -> under "Capability Request handling" -> Prohibit Virtual Hosts should not be selected.