UpPromote uses the Amazon email service to send emails to your affiliates. Using Amazon service, emails sent to your affiliates will have the sender's email address as [email protected] by default. In this default option, when an affiliate replies to an email, the merchant cannot receive it.
If you want to set up so that your email address is used as the sender's email, go to the Settings section and enable Use your email address as sender's:
By activating that feature, not only the merchant's email address would be displayed as the sender's email when sending to an affiliate, but also when an affiliate replies to an email, the merchant would receive that reply.