Email request not showing on customer portal

Email request not showing on customer portal

When a customer sends an email, which is then picked up in Zoho Support under requests, why does it not also show in the customer portal. Only requests made through the customer portal show in the portal. 

I want to allow my customers to log into the portal and see all  their requests, regardless of whether they sent them via emails or the customer portal. 

Perhaps I am missing something.