For me, it went well by choosing the zttap300 Driver manually for the created Zerotap Network Interface.
c:\ProgramFiles\ZeroTier\ZeroTierOneVirtualNetworkPort\zttap300
After that, the Networkconnection comes up immediately.
Fresh Win10 Pro 64bit up2date on ESXi 7.0 behind FritzBox 7590, Zerotier fresh install Zerotier 1.6.0
Bugs during installation seems to be only on Windows. On Mac and Iphone, there hadn´t been issues so far.
Br
Dominik