forticlient for iOS not working

How are FortiClient iOS devices connecting - SSLVPN web portal, or are they being restricted on-net or off-net?

no restrictions.

the user logging in has admin rights and have access to all the segments.

he installed the forticlient for IOS on his phone. 

should i asked him to try the web portal ??

Just to be clear, I mean: where are iOS clients connecting from? Internal to your network? Externally using a VPN? Externally through a VIP?

Where are the clients in terms of your network topology when their access attempts fail?

How far do iOS clients get in the telnet process before it fails? Can you provide a screenshot?

we are using sslvpn to login to office network from external. eg at home using normal  Internet line.

seems like IOS user cannot only do web browsing but not others like telnet or ssh or RDP to servers.

is sslvpn support in version 5.2.1 or 5.2.3 for IOS ?

You can use Java-based applets and connection tools within the SSLVPN web portal to initiate non-HTTP traffic to internal resources, but unfortunately, the SSLVPN app itself (FortiClient) does not create a traditional tunnel. You would not be able to use Safari or a native telnet app on the iPhone to connect to resources.

We're waiting on Apple for this.

Yes, to clarify, it's only FortiClient which would not allow you to create a tunnel connection. You can use the built-in IPSec client in iOS to connect to a FortiGate appliance. In OS 5.2, the FortiGate can even do most of the work for you behind the scenes if you opt for the wizard.

I can't see clearly from the summary lines why Phase 1 negotiations are failing.

Can you provide diagnostic output, or screenshots showing the details from one of those log messages?

diag debug reset

diag debug enable

diag debug application ike -1

<attempt to connect to the VPN, then...>

diag debug reset

diag debug disable