VPN connect problem

I am using FortiGate 100D

Connection failure occurs when attempting a VPN connection

No message occurs when connection fails

As a result of checking the server log, it occurred as follows. ------------------ Action: tunnel-down Reason: tunnel connection setup timeout for SSLVPN Client

------------------

After checking several attempts, I accidentally identified the following symptoms:

1. Confirm the message by entering the wrong password ------------------ Permission denied. (-445) ------------------

2. Try to log in again

Only in this case, strangely, you are logged in normally.

Can you see why this is happening?

* Environmental information FortiClient -Version 6.0.9.0277 FortiGate 100D -FortiOS v5.6.0, Build 1449