If your Linux distribution uses systemd, execute “sudo service zerotier-one start”
If not, execute “sudo /etc/init.d/zerotier-one start”
Still doesn’t work?
Your system firewall is likely blocking communication with the ZeroTier service. Look up instructions for how to unblock an application from the firewall for your OS. ZeroTier will need to be accessible via TCP port 9993 for the UI and CLI to interact with it.