Mail.app connection errors (offline) after sleep
This might seem weird and unlikely, but these steps (originally written to restore broken Dictation) fixed it for me:


Go to ~/Library/Preferences
( &#x21E7;+&#x2318;+G )
Locate com.apple.assistant.plist and move it to the Trash
Open Dictation &amp; Speech preference panel, disable dictation
Reboot
Re-enable Dictation &amp; Speech.


Any hints on why this is working are very welcome!