Topic: Autoresponses not received when using Mautic

- iRedMail version (check /etc/iredmail-release): 1.4.2
- Deployed with iRedMail Easy or the downloadable installer? Downloaded
- Linux/BSD distribution name and version: Ubuntu 20.04
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Nginix
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
- Marketing platform: Mautic 4.0.2

I am using the email marketing tool Mautic to send emails through iRedMail.
Mautic track bounces using an email account registered in iRedMail, this is done by checking a subfolder to inbox for bounces.

Unfortunately when we send an email to someone who has autoresponse activated, then there is no autoresponse sent back when using Mautic as sender. (Though undeliverable bounces get delivered to the folder in iRedMail.)

When I send the message manually to the same email (at gmail) from RoundCube, using the same iRedMail email account as when Mautic sends, then the autoresponse at gmail is activated. Then I can see the autoresponeded emails in RoundCube.

Anyone has a thought on how I can get the emails from Mautic that is sent through iRedMail to trigger the autoresponse?

Thank you ahead of time for any help