Outlook classic or modern doesn't work with SMTP Postfix: Modern TLS 1.3 only setting

Support
, ,
1

What type of hardware are you using: Virtual machine
What YunoHost version are you running: 12.1.39 and 13.0.4
How are you able to access your server: The webadmin
Are you in a special context or did you perform specific tweaking on your YunoHost instance ?: no

Describe your issue

Connecting Outlook Mail Client with Yunohost doesn’t work with “Modern (TLS 1.3 only)”.

If you set the Postfix-Compatibility setting to: “Modern (TLS 1.3 only)” it doesn’t work with Outlook.
You find it here: HOSTNAME/yunohost/admin/#/tools/settings/security

Solution:
Use “Intermediate (allows TLS 1.2)” as the security setting of postfix SMTP.

Share relevant logs or error messages

no need. I also provided the solution. Just for others to help them.

2

It does not (as in - you’ve tried and it did not work) or the string claims so (as in the description is outdated)?

3

Thanks for sharing this! Confirmed — Outlook doesn’t support TLS 1.3 only. Switching Postfix to “Intermediate” mode resolves the SMTP connection issue perfectly.

1 Like
4

I did the following tests with “Modern (TLS 1.3. only)” active for postfix SMTP server:

  1. Outlook Classic Window 11 latest update → Yunohost 12.1.39 or 13.0.4 → doesn’t work.
  2. Outlook Modern Apple MacOS Version 26.3.1 → Yunohost 12.1.39 or 13.0.4 → doesn’t work.
    → Outlook reports an error with the SMTP connection.
  3. With Thunderbird version 148.0 it works on both operating systems fine.

I did the following tests with “Intermediate (allows TLS 1.2)” active:

  1. Outlook Classic Window 11 latest update → Yunohost 12.1.39 or 13.0.4 → It works!
  2. Outlook Modern Apple MacOS Version 26.3.1 → Yunohost 12.1.39 or 13.0.4 → It works!
  3. With Thunderbird version 148.0 it works on both operating systems fine.
1 Like
5

This information is missing on this page:

6

By the power of open source the documentation can be update here: doc/docs/admin/35.email/05.clients.mdx at main · YunoHost/doc · GitHub :wink:

7

yes. this is the pull request: