centos 7 nmcli l2tp vpn using command line

**i try to create connection using lt2p vpn** > but my connection is not start [root@vps10337 system-connections]# nmcli connection add connection.id VPN_2 type vpn vpn-type l2tp connection.interface-name wlp2s0 ipv4.method auto vpn.data "gateway=xxx.xxx.xxx.xxx,ipsec-enabled= yes,ipsec-psk= 0s"$(base64 <<<'[PSK]' | rev | cut -c2- | rev)"=, mru = 1400, mtu = 1400, user=vpn, password-flags = 0, service-type=org.freedesktop.NetworkManager.l2tp , refuse-chap = yes, refuse-mschap = yes, refuse-pap = yes, require-mppe = yes, user=vpnuser " vpn.secrets password=vpnpass Connection 'VPN_2' (41de6cab-be8b-41f8-8c8e-86b1d057a477) successfully added. [root@vps10337 system-connections]# [root@vps10337 system-connections]# nmcli c up VPN_2 Error: Connection activation failed: The VPN service failed to start