KB-1887 Appian 18.4 custom email sender functionality "Return-Path" and "Sender" fields differ from the old custom email sender functionality


When testing the new feature to Configure Custom Email Senders Inline, emails may not be received by certain mail servers. Upon further inspection, it is seen that the Sender and the Return-Path headers are not the same as the From header (which is the value configured in the Sender Email field configured in the Send Email Smart Service node).

For example, the Send Email Smart Service node is configured as follows:

However, instead of seeing "help@example.com" in the Sender header and the Return-Path header (as the pre-18.4 custom email senders would display), these headers display a different value such as "admin@siteurl.appianurl.com" as seen below:

Return-Path: <admin@siteurl.appianurl.com>
From: IT Service Desk <help@example.com>
Sender: <admin@siteurl.appianurl.com>

This may result in emails failing to deliver to certain servers if these servers only accept mail from the domain "*@example.com" and block mail from other domains such as "*@siteurl.appianurl.com" or "*@siteurl.appiancloud.com".


This is the intended design for the Appian 18.4 Configure Custom Email Senders Inline feature. Since the feature introduced the ability for any designer to select any sender email and sender display name, it became important to make it explicitly clear that the email is being sent by the system on behalf of an email address, rather than from the email address directly.

Therefore, the feature will set the Sender header and the Return-Path header to the #site value specified in the conf.mailhandler.ntf_sndr_addr property in custom.properties. In Appian Cloud, the default value for this property is of the form "admin@subdomain.appiancloud.com".


Appian Self-managed

Change the conf.mailhandler.ntf_sndr_addr property in custom.properties to an email address with the desired domain. In this case, setting the value to admin@example.com will suffice.

Appian Cloud

Create an Appian Support case to request to change the notification sender email address property to an email address with the desired domain (rather than *@subdomain.appiancloud.com). In this case, requesting to set the value to admin@example.com will suffice.

Affected Versions

This article applies to Appian 18.4 and later.

Last Reviewed: March 2019