I changed my password in Google Mail yesterday. This morning, Mail.app was not able to access nor was my iCal.
So obviously there is another step that I did not know to take.
You just need to plug the new password into a few places:
- Apple Mail (Mail menu > Preferences > Accounts > Incoming Mail Server settings, and also click “Edit SMTP Server List” in the Outgoing Mail Server drop-down)
- iCal (iCal > Preferences > Accounts)
- iPhone (Settings > Mail, Contacts, and Calendar > tap on your account, change the password in Account Information and also in Outgoing Mail Server > Primary Server).