Troubleshooting Tip : Windows 7 users are unable to connect to SSLVPN due to DH-Params mismatch.

This article describes how to fix the problem wherein Windows 7 users encounter the FortiClient message 'The server you want to connect to requests identification, please choose a certificate and try again.(-5)' when connecting to SSLVPN.

Problem.

In this example, the FortiGate was using 8192 DH Params on its settings:

Solution.

# config sys global

       unset dh-params

   end

Unsetting DH-params will revert its value to the default one which is 2048. 

Results.

PS: Note however that this article is one of the possibilities in relation to this error as it could also mean other things and points to other problems.