I have a problem with L2TP VPN. I used Ubuntu 18.04 and installed network-manager-l2tp, network-manager-l2tp-gnome, but I failed to connect company's L2TP VPN. The following is syslog.
Jul 1 18:13:24 linyong-PC charon: 12[ENC] parsed INFORMATIONAL_V1 request 4104919682 [ N(NO_PROP) ]
Jul 1 18:13:24 linyong-PC charon: 12[IKE] received NO_PROPOSAL_CHOSEN error notify
Jul 1 18:13:24 linyong-PC NetworkManager[1077]: establishing connection 'dcbd7b48-3e65-4b14-92c7-f906f159cd70' failed
Jul 1 18:13:25 linyong-PC NetworkManager[1077]: Stopping strongSwan IPsec...
Jul 1 18:13:25 linyong-PC charon: 00[DMN] signal of type SIGINT received. Shutting down
Jul 1 18:13:25 linyong-PC nm-l2tp-service[23236]: g_dbus_method_invocation_take_error: assertion 'error != NULL' failed
Jul 1 18:13:25 linyong-PC NetworkManager[1077]: <info> [1561976005.2076] vpn-connection[0x555810a8c810,dcbd7b48-3e65-4b14-92c7-f906f159cd70,"VPN 1",0]: VPN plugin: state changed: stopped (6)
Jul 1 18:13:25 linyong-PC NetworkManager[1077]: <info> [1561976005.2122] vpn-connection[0x555810a8c810,dcbd7b48-3e65-4b14-92c7-f906f159cd70,"VPN 1",0]: VPN service disappeared
Jul 1 18:13:25 linyong-PC NetworkManager[1077]: <warn> [1561976005.2133] vpn-connection[0x555810a8c810,dcbd7b48-3e65-4b14-92c7-f906f159cd70,"VPN 1",0]: VPN connection: failed to connect: 'Message recipient disconnected from message bus without replying'
I am able to connect the VPN in Windows 10, I don't know if I missed some config. What can I do?