Case 2: The Producer in question does not yet have a user account with OFN:
In this case, you can not find their email when you type in the box 'Add an Existing User'. You must then click on "Add an Unregistered User" just below, next to the 'Invite Manager' field.
The producer will then receive an email from us to confirm their registration. On following the instructions detailed in the email they will be able to complete setting up their OFN account, including adding a password.