Technical Tip: Windows 7 users unable to connect to SSL-VPN via FortiClient

This articles describes the error message 'The server you want to connect requests identification, please choose a certificate and try again (-5)'.

Debug log:

[227:root:377]SSL state:SSLv3/TLS write server done:DH lib(IPx.x.x.x)
[227:root:377]SSL_accept failed, 5:(null).

Packet capture showing client machine only support Diffie-Hellman key exchange value 1024.

Set the dh-params to 1024 as below and resolve SSL-VPN connection issue.

# config system global
    set dh-params 1024
  end