To set up Google Sync on your Windows Mobile device, please follow the steps below.
Important Note: Make sure that you have backed up any Contacts and Calendars from your phone to your computer before proceeding.
Getting Started

To set up Google Sync on your Windows Mobile device, please follow the steps below.
Important Note: Make sure that you have backed up any Contacts and Calendars from your phone to your computer before proceeding.
Getting Started
1. Open the Microsoft Exchange ActiveSync application on your device’s home screen.
2. Click Set up your device to sync with it.
3. Enter m.google.com as the server address.
4. Ensure that the SSL option is selected.

Sign In to Your Google Account
5. Click Next.
6. Enter your full Google Account email address as the User name.
7. Enter your Google Account password as the Password. If you’re a 2-step verification user, please use an application-specific password instead.
8. Leave the Domain field empty. If your device requires you to enter a domain name, enter google.
9. Click Next.
10. Check Contacts, Calendar, or Email, depending on which you’d like to sync. (Tasks is not supported and will lead to an error if checked.)
11. Click Finish.

12. Press the Sync softkey on the left to synchronize.

Note, to fix any connection problem, use:
Once that’s done. Open ActiveSync -> Menu -> Options.
You’ll find Exchange Server (the one to sync with google). In there, UN-SELECT TASKS.
And try to sync your device now.It should work.