Resolve the "failed to sync Contacts" issue.

If you're having trouble to push your Gmail contacts to your Android phone, try the following steps:

1. Backup your Gmail contacts. Go to your Gmail contacts page, click More actions and then select Export... to download a copy of your current contacts.
2. If you update some contacts information on your phone after it failed to sync, you need to manually update the changes to your Gmail contacts online.
3. Make sure you Gmail contacts have all updated contact information.
4. Erase all contacts on your Android phone. Go to your phone Settings > Applications > Manage Application. Go to All tab and search for Contacts Storage. (Tips: you can search the list by pressing the search button on your phone.) Open Contacts Storage and click Clear data.
5. Once it's done, you can wait for next update or go to Settings > Account & Sync and click Sync all to force immediate update.

Now, the contacts on your phone should be identical to the one on your Gmail.