OpenVPN TLS 오류

OpenVPN을 사용하는 데 문제가 있습니다.

Centos 컴퓨터에 OpenVPN을 설치하고 구성했는데 모든 것이 잘 진행되는 것 같습니다. 아래 링크의 지침을 따랐습니다.

https://www.digitalocean.com/community/tutorials/how-to-setup-and-configure-an-openvpn-server-on-centos-6

클라이언트 컴퓨터에 연결하려고 하면 다음과 같은 메시지가 나타납니다.

TLS Error: TLS key negotiation failed to occur within 60 seconds

전체 로그입니다

Mon Mar 30 18:55:11 2015 OpenVPN 2.3.6 x86_64-w64-mingw32 [SSL (OpenSSL)] [LZO] [PKCS11] [IPv6] built on Mar 19 2015
Mon Mar 30 18:55:11 2015 library versions: OpenSSL 1.0.1m 19 Mar 2015, LZO 2.08
Enter Management Password:
Mon Mar 30 18:55:11 2015 MANAGEMENT: TCP Socket listening on [AF_INET]127.0.0.1:25340
Mon Mar 30 18:55:11 2015 Need hold release from management interface, waiting...
Mon Mar 30 18:55:11 2015 MANAGEMENT: Client connected from [AF_INET]127.0.0.1:25340
Mon Mar 30 18:55:11 2015 MANAGEMENT: CMD 'state on'
Mon Mar 30 18:55:11 2015 MANAGEMENT: CMD 'log all on'
Mon Mar 30 18:55:11 2015 MANAGEMENT: CMD 'hold off'
Mon Mar 30 18:55:11 2015 MANAGEMENT: CMD 'hold release'
Mon Mar 30 18:55:11 2015 WARNING: No server certificate verification method has been enabled.  See http://openvpn.net/howto.html#mitm for more info.
Mon Mar 30 18:55:12 2015 Socket Buffers: R=[8192->8192] S=[8192->8192]
Mon Mar 30 18:55:12 2015 UDPv4 link local: [undef]
Mon Mar 30 18:55:12 2015 UDPv4 link remote: [AF_INET]192.168.20.17:1194
Mon Mar 30 18:55:12 2015 MANAGEMENT: >STATE:1427734512,WAIT,,,
Mon Mar 30 18:56:12 2015 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)
Mon Mar 30 18:56:12 2015 TLS Error: TLS handshake failed
Mon Mar 30 18:56:12 2015 SIGUSR1[soft,tls-error] received, process restarting
Mon Mar 30 18:56:12 2015 MANAGEMENT: >STATE:1427734572,RECONNECTING,tls-error,,
Mon Mar 30 18:56:12 2015 Restart pause, 2 second(s)
Mon Mar 30 18:56:14 2015 WARNING: No server certificate verification method has been enabled.  See http://openvpn.net/howto.html#mitm for more info.
Mon Mar 30 18:56:14 2015 Socket Buffers: R=[8192->8192] S=[8192->8192]
Mon Mar 30 18:56:14 2015 UDPv4 link local: [undef]
Mon Mar 30 18:56:14 2015 UDPv4 link remote: [AF_INET]192.168.20.17:1194
Mon Mar 30 18:56:14 2015 MANAGEMENT: >STATE:1427734574,WAIT,,,
Mon Mar 30 18:56:17 2015 SIGTERM[hard,] received, process exiting
Mon Mar 30 18:56:17 2015 MANAGEMENT: >STATE:1427734577,EXITING,SIGTERM,,

방화벽을 완전히 비활성화하려고 시도했지만 문제가 해결되지 않은 것 같습니다.

이 문제를 어떻게 해결할 수 있는지 아는 사람 있나요?