Hi,
sudo netfilter-persistent save
and when you get a chance, reboot the pi and make sure the vpn comes up.
I think the bits you are missing are creating the timer, starting and enabling; all you have created is the service. I think these should get it going:
sudo nano /etc/systemd/system/openvpn-watchdog.timer
:
[Unit]
Description=OpenVPN Watchdog timer
[Timer]
OnCalendar=*:0/15
[Install]
WantedBy=timers.target
Then issue:
sudo systemctl start openvpn-watchdog.timer
sudo systemctl enable openvpn-watchdog.timer
Thanks Tom.