KB-1257 "<IP address> is not allowed to send mail from <domain>" error thrown when using the Send Email smart service

Symptoms

One or more recipient addresses do not receive emails from Appian via the Send Email node. The SMTP logs show the following error:

<IP_address> is not allowed to send mail from <domain> (in reply to RCPT TO command))

Cause

The SMTP server that is configured with Appian is not on the allowed list for the recipient’s email server.

Action

The recipient’s email server needs to be configured to allow emails from Appian’s SMTP server. Alternately, emails from Appian can be rerouted to an SMTP server that is on the allowed list for the recipient’s email server.

Affected Versions

This article applies to all versions of Appian.