openfortivpn 连接进度在“连接到网关”后停止

Question

尝试从 Linux (Mint) 机器连接工作中的 SSL VPN。使用嵌入式客户端在 Windows 10 上工作正常。在 Mint 上，我尝试使用 openfortivpn（使用不同版本：Mint 19.3 上的 1.6.1 和 1.14.1 以及 Mint 20.1 上的 1.12.1）

>> openfortivpn host.name:443 --username=user --insecure-ssl -v
DEBUG:  openfortivpn 1.14.1
DEBUG:  revision unavailable
DEBUG:  Loaded config file "/etc/openfortivpn/config".
VPN account password: 
DEBUG:  Config host = "host.name"
DEBUG:  Config realm = ""
DEBUG:  Config port = "443"
DEBUG:  Config username = "user"
DEBUG:  Resolving gateway host ip
DEBUG:  Establishing ssl connection
DEBUG:  server_addr: a.b.c.d
DEBUG:  server_port: 443
DEBUG:  gateway_addr: a.b.c.d
DEBUG:  gateway_port: 443
DEBUG:  Setting minimum protocol version to: 0x303.
DEBUG:  Gateway certificate validation succeeded.
INFO:   Connected to gateway.

然后就停在这里了。没有进一步的进展。系统中没有出现 PPP 接口。/etc/openfortivpn/config 为空。有没有办法继续并完成连接？

nmap以下是有关服务器协议的信息：

443/tcp open  https
| ssl-enum-ciphers: 
|   TLSv1.0: 
|     ciphers: 
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 1024) - A
|       TLS_RSA_WITH_RC4_128_SHA (rsa 1024) - D
|     compressors: 
|       NULL
|     cipher preference: client
|     warnings: 
|       Broken cipher RC4 is deprecated by RFC 7465
|   TLSv1.1: 
|     ciphers: 
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 1024) - A
|       TLS_RSA_WITH_RC4_128_SHA (rsa 1024) - D
|     compressors: 
|       NULL
|     cipher preference: client
|     warnings: 
|       Broken cipher RC4 is deprecated by RFC 7465
|   TLSv1.2: 
|     ciphers: 
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 1024) - A
|       TLS_RSA_WITH_RC4_128_SHA (rsa 1024) - D
|     compressors: 
|       NULL
|     cipher preference: client
|     warnings: 
|       Broken cipher RC4 is deprecated by RFC 7465
|_  least strength: D