Last updated: 2017-07-24

Source: https://support.freshdesk.com/support/solutions/articles/226852-while-adding-a-new-product-i-get-the-error-message-please-enter-a-valid-email-address-why-so-

For each portal on your account, you would have one dedicated primary email address associated with it. The main portal will have a similar primary support email and the product portal will have it's own distinct primary email address.

Existing emails cannot be used while creating a new product. You would have to add a new/unique email address and associated it with the New Product which is being created.