Email reply to customer is sent four times

Technical assistance
1

Servus Zammad!

Infos:

  • Used Zammad version: 6.3.1-121
  • Used Zammad installation type: docker-compose
  • Operating system: Ubuntun 24.04 LTS Server
  • Browser + version: Chrome 128.0.6613.84 on Linux

Expected behavior:

  • When replying a customer in an open ticket by mail, send the mail only once.
    This is a new deployment which

Actual behavior:

  • Customer receives four mails with identical content. Mail server log shows four messages/connections from Zammad_Mail_Service.

Timestamps from mail server:

Sep  2 09:05:34
Sep  2 09:06:03
Sep  2 09:06:56
Sep  2 09:08:12

Steps to reproduce the behavior:

  • On my system: Just send an email to a customer.

Question:

  • Any idea what could cause this issue?
  • Where can I find email logs in a docker-compose environment?
  • How to debug email issues like SMTP or IMAP polling?
2

I suspect this issue being caused by wrong access rights when changing backend storage from DB to FILESYSTEM.

Need to execute “chown -R 1000:1000 _data” within the volume.