OpenVPN su Azbox premium HD+

Sto provando ad installare Openvpn su un Azbox premium HD+ con firmware originale (0.9.5402), ma non funziona :-(
Voglio collegarmi ad un server Openvpn Free, ne ho provati diversi ma la risposta di errore sembra sempre la stessa:
VERIFY ERROR: depth=0, error=certificate signature failure

(Utilizzo MaZ 3.2 - Manager for Azbox- sia per modificare file config e certificati via ftp, sia per il telnet)

In dettaglio:
Dopo aver caricato tun.ko con il comando "/sbin/insmod -v tun.ko"
Invio il seguente comando per lanciare Opnevpn "opt/sbin/openvpn --config /DISK2/etc/openvpn/client.conf"

di risposta ottengo (che si ripete all'infinito) :

AZBox[openvpn]$ /opt/sbin/openvpn --config /DISK2/etc/openvpn/client.conf
Sat Sep 10 22:45:27 2016 OpenVPN 2.2.0 mipsel-linux [SSL] [LZO2] [EPOLL] [eurephia] built on Feb 18 2012
Sat Sep 10 22:45:27 2016 NOTE: OpenVPN 2.1 requires '--script-security 2' or higher to call user-defined scripts or executables
Sat Sep 10 22:45:27 2016 LZO compression initialized
Sat Sep 10 22:45:27 2016 Control Channel MTU parms [ L:1560 D:140 EF:40 EB:0 ET:0 EL:0 ]
Sat Sep 10 22:45:27 2016 Socket Buffers: R=[87380->131072] S=[16384->131072]
Sat Sep 10 22:45:27 2016 Data Channel MTU parms [ L:1560 D:1450 EF:60 EB:135 ET:0 EL:0 AF:3/1 ]
Sat Sep 10 22:45:27 2016 Local Options hash (VER=V4): 'f1b546b6'
Sat Sep 10 22:45:27 2016 Expected Remote Options hash (VER=V4): 'aa1721bb'
Sat Sep 10 22:45:27 2016 Attempting to establish TCP connection with 122.116.129.7:443 [nonblock]
Sat Sep 10 22:45:28 2016 TCP connection established with 122.116.129.7:443
Sat Sep 10 22:45:28 2016 TCPv4_CLIENT link local: [undef]
Sat Sep 10 22:45:28 2016 TCPv4_CLIENT link remote: 122.116.129.7:443
Sat Sep 10 22:45:30 2016 TLS: Initial packet from 122.116.129.7:443, sid=8eae1faf c895329c
Sat Sep 10 22:45:30 2016 VERIFY ERROR: depth=0, error=certificate signature failure: /CN=xjmh7w8q.com/O=882idmmt_qmi8b74kwu/C=US
Sat Sep 10 22:45:30 2016 TLS_ERROR: BIO read tls_read_plaintext error: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
Sat Sep 10 22:45:30 2016 TLS Error: TLS object -> incoming plaintext read error
Sat Sep 10 22:45:30 2016 TLS Error: TLS handshake failed
Sat Sep 10 22:45:30 2016 Fatal TLS error (check_tls_errors_co), restarting
Sat Sep 10 22:45:30 2016 TCP/UDP: Closing socket
Sat Sep 10 22:45:30 2016 SIGUSR1[soft,tls-error] received, process restarting
Sat Sep 10 22:45:30 2016 Restart pause, 5 second(s)
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Saluto e ringrazio in anticipo.