OPENVPN: PolarSSL: ca certificated is undefined

[mototopo2016]

Hello everyone, I have this problem:
I downloaded the application OpenVPN CONNECT 1.1.17 build 76 of Android 5.1
The certificate that I created on my pfsense works fine on PC with windows 10 and I connect perfectly.
On the phone instead always I get the error message: PolarSSL: ca certificate is undefined

In practice I have only two files:
OVPN the file and the secret

I am attaching my configuration hiding addresses and key.
this is my ovpn

dev tun
persist-tun
persist-key
proto tcp-client
cipher BF-CBC
auth SHA1
;pull
resolv-retry infinite
remote xx.xx.xx.xx 1196
route 192.168.42.0 255.255.255.0
ifconfig 10.4.0.6 10.4.0.5
keepalive 10 60
ping-timer-rem
secret FW3A-1196.secret
comp-lzo
passtos

and the file secret is:

#
# 2048 bit OpenVPN static key
#
-----BEGIN OpenVPN Static key V1-----
deleted from me
-----END OpenVPN Static key V1-----

I can not understand where I'm wrong.
Can you give me a hand?

[TinCanTech]

https://community.openvpn.net/openvpn/wiki/IOSinline