Mail.app can’t connect after 10.4.7 upgrade?
Thursday, June 29th, 2006
Several people in the Apple Discussion forums have reported 
that they are unable to connect to their mail servers after applying the 10.4.7 update.
The problem is (usually) that Mail.app’s new ability to connect through a SOCKS proxy had been turned on during the update.
The fix is simple.
Open up your the Network pane of your System Preferences. Choose your current method of connecting to the Internet (Built-in Ethernet, Airport, etc) and select the Proxies tab on the configuration dialog.
Make sure that the SOCKS proxy box is unchecked:
