To include the unassigned email in a customer timeline you will need to assign the email to that specific customer.
Actions board ➡️ To-Do List ➡️ Unassigned customer communications ➡️ Select Email ➡️ Type in Customer ➡️ Click Assign
To assign your emails go into your actions board
Select your to-do-list tab – you should see the unassigned emails highlighted just under your tab selections
Click on view & assign
This will bring up the list of all unassigned emails
Select an email this will open up the email in preview – there is a bar on the top where you can type in the customer name & click assign