Unable to verify account name or password - Gmail

Ok, I solved the problem. Just realized that I have all the security activated on my gmail account.

If you have similar issues with setting up you Gmail account on Mac you need to do the following in your gmail account setings:

1. In your gmail account go to Settings (cog wheel in the top right)

2. Go to Accounts and Imports tab

3. Go to Change account settings --> Other Google Account settings

4. Click on Security

5. Scroll to the bottom of the screen and click on 'Manage access':

6. Verify your password

7. In the field provided enter the name of your device (could be anything it's just for your information to know which of your devices are given full access to the gmail account)

8. Click on "Generate password"

9. Password will appear in the yellow field

10. Copy this password and paste it in the password field in your Mail, Contacts & Calendar in System Preferences.

11. This is one off password only used to grant an access to your gmail account by your device.

12. You need to use your standard gmail password from now on.

You're done and your gmail email is downloaded to Mac Mail!