Smart Docs esignature emails get sent from a pipedrive email account? Why?

Boppa

Our customers reply to proposals via a reply email all the time. Why is this email coming from Pipedrive so customers can't reply? Customers often won't go into the proposal and use the response tools inside - we have a lot of Mum & Dad users - so their reply is critical and often contains vital info for our reps prior to signing.