New Zoho account adding Mail user

I've been in the trial period for CRM and Mail, and have just signed up in both for a two user license. I'm trying to add a second user to Mail, so we can share the same POP accounts that have been set up in my Mail account. The invitation to her is showing as pending, and has not been received at her email address. When I tried to use the option to import a CRM user to Mail, it confirms, but nothing changes in my User Details page - I am the only one listed.