Invalid host address for Nokia E71 exchange

i'm trying to setup my Nokia E71 with my school Exchange email. I have checked to see it's enabled for mobile devices.

I have downloaded the latest version of Mail for Exchange but getting the following error when attempting to connect:

"Invalid host address. Correct the Exchange server information Profile > Connection"

I have simply entered 'exchange' as the server name as this is what it is called and have selected a non-secure connection.

I was wondering if anyone knew why the above error appears? Or if there is an alternative way to insert the Exchange server. I have attempted to put the IP address but it simply says "cannot connect".

Your help will be much appreciated.