TG Client comes with built in TUN/TAP drivers that allow your VPN connection to be created. However if TG Client is unable to load these drivers you may see an error like "Cannot allocate TUN/TAP dev dynamically" in the OpenVPN log.
In most instances this error is caused by the VPN app having incorrect permissions. This can usually be solved by making sure TorGuard Client is installed in your Applications folder. TG Client is unable to correctly run from some locations (such as your Downloads folder, or your Home directory if FileVault is on). TG Client can be moved to the Applications folder like so:
If TG Client is already installed in your Applications folder, try re-installing the latest version.. This can be done like so:
If you are still getting the error, it's possible that other VPN clients (such as Cisco AnyConnect) may be interfering with TorGuard's TUN/TAP drivers. If you have any such clients installed, try temporarily quitting and/or uninstalling them to see if that solves the problem.
Finally, it's possible there may be a temporary conflict. Try restarting your computer and connecting TG Client again.