Translation of Email string

Hi,

I am having a problem that I can’t fix. I use loco translate, and I have translated this string in Loco. But in the e-mail sent to my customers (order email sent automatically when completed), the string:

Your License Key(s)

is not being translated.

How can I translate that title that is added to the license section of the order email?

Thank you!

PS: I intend to make the pt_BR translation, this plugin is awesome and the team behind it are too. Thank you for that.