If we look at the client side of Workplace Join process it says that we should log on with Microsoft account, but I've never seen it mentioned that Microsoft account is a requirement for Workplace Join. Recently I performed server side setup for Workplace Join on my test server using the following steps:
"Why Windows Server 2012 R2: Step-by-Step Workplace Join, Bringing Peace of Mind for BYOD"
Unfortunately I was not able to perform Windows 8.1 VM join following those steps:
Walkthrough: Workplace Join with a Windows Device
Could it be because of using local instead of Microsoft account? Am I missing something else here? Network connectivity between VMs is checked.