UAVmatrix has made an agreement with zerotier engineering allowing us to bundle UAVcast-Pro with their application for non-commercial customers. We also developed our own zerotier controller https://uavnet.uavmatrix.com.
If you are unsure about your login credentials, please register at https://uavmatrix.com/my-account/ with the same email address used for UAVcast-Pro purchase and you will find the login details under "orders".
All new customers will get an account at uavnet.uavmatrix.com with same expire date as the UAVcast-Pro license.
Zerotier usage instruction are described in uavnet dashboard.