iPhones and Blackberry’s not connecting to Exchange Server

On Wednesday our BT BusinessHub failed and BT sent us a new one the next day. I plugged it in and set the IP, Subnet etc on the router to what the failed router was. All Emails are being sent and received from the computers but the iPhones and Blackberry’s won’t connect to the Exchange Server.

I get the following on the iPhones:
‘Cannot Get Mail
The connection to the server failed’

As nothing on the phones have changed and as the computers are all sending and receiving mail without any issues I’m guessing I need to change something on the Hub to allow the phones to connect to the server.

BT BusinessHub Model: BT2700HGV
Microsoft Windows Small Business Server 2003
ActiveSync is set in Exchange System Manager -> Global -> Mobile