So you’ve changed your Google account password. The only problem is your Droid has your old password still stored and you can’t retrieve your Gmail. Follow these steps to enter a new password on your Droid.
1. Open Gmail and press Menu > Refresh. The sync will fail.
2. Close Gmail and slide down the notification bar.
3. Tap the Sign-in error… option.
4. You will be prompted to enter your new password. Tap Sign in when done.