strongSwan failed to start

I am configuring L2TP VPN on Ubuntu 20.4 client. After the following installation from this site, when I want to restart ipsec /usr/sbin/ipsec start I get this error:

Starting strongSwan 5.8.2 IPsec [starter]...
charon is already running (/var/run/charon.pid exists) -- skipping daemon start
/etc/ipsec.conf:1: missing value for setting 'config'
invalid config file '/etc/ipsec.conf'
unable to start strongSwan -- fatal errors in config

What's the solution?

Here it is of my /etc/ipsec.conf:

My newest update (2020-07-10)

root@ubuntu:/home/username# /usr/sbin/ipsec start
Starting strongSwan 5.8.2 IPsec [starter]...
charon is already running (/var/run/charon.pid exists) -- skipping daemon start
/etc/ipsec.conf:2: missing value for setting 'conn'
invalid config file '/etc/ipsec.conf'
unable to start strongSwan -- fatal errors in config