Comment 4 for bug 1651458

I got similar problem in openSUSE Tumbleweed and found out that openvpn package was upgraded to version 2.4 but my openvpn configs were created for version 2.3.
Openvpn 2.4 is incompatible with old configs, so you should either rewrite conflicting parameters to the new format or downgrade openvpn package to 2.3.*.

Tags for google, please ignore:
Error: Connection activation failed: Unknown reason
Warning: password for 'vpn.secrets.password' not given in 'passwd-file' and nmcli cannot ask without '--ask' option.