An internal FYI user has been set up as a Client or as a Client's Contact and has their email address in the Client or Contact record in Xero Practice Manager.
Even if the client has Include in AutoFile set, this will cause emails to not be autofiled.
This could be, for example, where the internal user also uses the practice for their tax returns, or is associated with the Client as a Contact. This could also have been set when trialing or when testing within FYI.
Where the FYI user is also a client, change the email address of the user in the Client record in Xero Practice Manager. The client email should be set as their personal email, not their work email.
Where this is set as the Contact record in Xero Practice Manager, you need to remove the Contact in Xero Practice Manager and add it again with the personal email address.
Note: Changing the internal user's email in the client, or changing the contact, will only change this for future emails.