got the same issue here. it works fine from the commandline, but via 
network-manager-openvpn I get the following error (same as above).

I use a preshared key too.


Jul 26 18:45:59 trinity NetworkManager: <info>  Will activate VPN connection 'stern', service 'org.freedesktop.NetworkManager.openvpn', user_name 'up', vpn_data 'connection-type / shared-key / dev / tun / remote / 213.208.137.47 / port / 1194 / proto / udp / servercert-insecure / no / ca /  / cert /  / key /  / comp-lzo / yes / shared-key / /home/up/roterstern_openvpn.key / local-ip / 10.1.0.2 / remote-ip / 10.1.0.1 / username / ', route ''. 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 1 of 4 (Connection Prepare) scheduled... 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 1 of 4 (Connection Prepare) ran VPN service daemon org.freedesktop.NetworkManager.openvpn (PID 2474) 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 1 of 4 (Connection Prepare) complete. 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 2 of 4 (Connection Prepare Wait) scheduled... 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN service 'org.freedesktop.NetworkManager.openvpn' signaled state change 1 -> 6. 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 2 of 4 (Connection Prepare Wait) waiting... 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 2 of 4 (Connection Prepare Wait) complete. 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 3 of 4 (Connect) scheduled... 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 3 of 4 (Connect) sending connect request. 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 3 of 4 (Connect) request sent, waiting for reply... 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN service 'org.freedesktop.NetworkManager.openvpn' signaled state change 6 -> 3. 
Jul 26 18:45:59 trinity nm-openvpn[2477]: Options error: Parameter ns_cert_type can only be specified in TLS-mode, i.e. where --tls-server or --tls-client is also specified.
Jul 26 18:45:59 trinity nm-openvpn[2477]: Use --help for more information.
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 3 of 4 (Connect) reply received. 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 4 of 4 (IP Config Get) timeout scheduled... 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN Activation (stern) Stage 3 of 4 (Connect) complete, waiting for IP configuration... 
Jul 26 18:45:59 trinity NetworkManager: <WARN>  nm_vpn_service_process_signal(): VPN failed for service 'org.freedesktop.NetworkManager.openvpn', signal 'ConnectFailed', with message 'The VPN login failed because the VPN program could not connect to the VPN server.'. 
Jul 26 18:45:59 trinity NetworkManager: <debug> [1217090759.633709] nm_dbus_signal_filter(): NetworkManagerInfo triggered update of VPN connection 'stern' 
Jul 26 18:45:59 trinity NetworkManager: <info>  VPN service 'org.freedesktop.NetworkManager.openvpn' signaled state change 3 -> 6. 
Jul 26 18:45:59 trinity NetworkManager: <WARN>  nm_vpn_service_stop_connection(): (VPN Service org.freedesktop.NetworkManager.openvpn): could not stop connection 'stern' because service was 6.