I am attempting to get ActiveSync by Autodiscover working correctly on a new Exchange 2010 install
DMZ - TMG 2010
LAN Multirole Exchange 2010 SP3 Server
I am seeing the following in the TMG logs
Status 12309 The server requries authorization to fullfill the request. Access to the Web server is denied.
Request POST http://autodiscover.domain.co.uk/Autodiscover/Autodiscover.xml
The authorization delegation for this rule is set to Basic Authentication
Active Sync works if you fill in the details manually