As I stated, it's broken and doesn't work.
Despite entering an en email address here (custom envelope is already active), you system just changes it to 'discard:[127.0.0.1]' immediately afterwards.
Pepipost representative Prathamesh Walke already acknowledged, via support email response, 3 days ago that this functionality is broken.
Since putting site emails through Pepipost, I found;
- Too many recipient mail servers bouncing due to Pepipost having poor DNSBL reputation (you fixed by moving me to a different sender ip address)
- Bounced email notification functionality doesn't work
- Click tracking functionality that replaces 'base href' statements within emails, and thus causes image URL's within emails to fail
It really feels to me like Pepipost is a beta service and has a way to go before it's ready for usage that relies on email communication/marketing.