Problem running openvpn (OpenVZ,lxd)

OS: Ubuntu 16.04 x64 running on OpenVZ

Workaround:

• comment out the LimitNPROC line in /lib/systemd/system/openvpn@.service
• systemctl daemon-reload

root@vps:~# systemctl status openvpn@server
Б≈▐ openvpn@server.service - OpenVPN connection to server
   Loaded: loaded (/lib/systemd/system/openvpn@.service; disabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Tue 2018-10-30 13:44:33 UTC; 19h ago
     Docs: man:openvpn(8)
           https://community.openvpn.net/openvpn/wiki/Openvpn23ManPage
           https://community.openvpn.net/openvpn/wiki/HOWTO
  Process: 5666 ExecStart=/usr/sbin/openvpn --daemon ovpn-%i --status /run/openvpn/%i.status 10 --cd /etc/openvpn --script-security 2 --config /etc/openvpn/%i.conf --writepid /run/openvpn/%i.pid (code=exited, status=1/FAILURE)

Oct 30 13:44:33 vps.server.com systemd[1]: Starting OpenVPN connection to server...
Oct 30 13:44:33 vps.server.com ovpn-server[5666]: daemon() failed or unsupported: Resource temporarily unavailable (errno=11)
Oct 30 13:44:33 vps.server.com systemd[1]: openvpn@server.service: Control process exited, code=exited status=1
Oct 30 13:44:33 vps.server.com systemd[1]: Failed to start OpenVPN connection to server.
Oct 30 13:44:33 vps.server.com systemd[1]: openvpn@server.service: Unit entered failed state.
Oct 30 13:44:33 vps.server.com systemd[1]: openvpn@server.service: Failed with result 'exit-code'.
root@vps:~# journalctl | grep ovpn-server | tail -n 100
Oct 30 13:44:33 vps.server.com ovpn-server[5666]: daemon() failed or unsupported: Resource temporarily unavailable (errno=11)