I created user in Zoho CRM

User got invitation by email and clicked on the link inside invitation, then he did first login in with his Google Apps Account instead of creating password and Zoho login name. Zoho CRM allowed user to login to Zoho CRM with his Google Apps account. But I have to configure Zoho CRM Mail Add-On and it asks me the password for Zoho Mail (user does not input any Zoho Mail password because he logged in first with the federate login from Google Apps). Now I am not able to connect user's Zoho Mail to Zoho CRM because of this password - is it possible to create the possibility for the Zoho CRM Mail Add-On to login with the Federate login from Google Apps? what is your estimation of the project duration? Do I have any work around: to create Zoho Mail password for the user?