Zerotierone: Does not stop during Ubuntu system shutdown/reboot

[allenap]

Describe the bug

The ZeroTier service does not stop when shutting down or rebooting Ubuntu. It hangs for 1m30s while systemd (I assume) waits before forcefully killing it.

Expected behavior

The service should exit within a few seconds of being asked to do so by systemd.

Screenshots

Desktop (please complete the following information):

• OS: Ubuntu 18.04.4 (Bionic), all system packages up to date
• ZeroTier Version: 1.4.6 (from .deb package)
  $ cat /etc/apt/sources.list.d/zerotier.list deb http://download.zerotier.com/debian/bionic bionic main
• Hardware: x86_64, Intel

Additional context

• ZeroTier Network Configuration: A couple of networks, nothing fancy, a handful of devices.
• Router Config: Regular home router.
• Firewall Config (try turning the firewall off): None.
• General Network Environment: Home.

[laduke]

check #1093 for some ideas @allenap. you can adjust the unit file for a work around.

[pinduzera]

Just as an add.
I face the same problem on Pop!_OS 20.04