Hi,
i just updated Zerotier on two of my Windows 2016 Servers for testing. Both servers fail to connect to any host, Zerotier Central show both server as online. I took a look in network control panel and found that the Zerotier update process disabled the Zerotier One interface for the network and another “Ethernet 2” of type “Zerotier One Virtual Port” connect/disconnect around two times per second.
I solved it by stopping ZT service, re enable the Zerotier One Interface for the Network and started ZT service again, connection works now and the the flapping one just stays enabled but disconnected.