Unable to send email - can't modify frozen String: "execution expired

Technical assistance
1

Infos:

  • Used Zammad version: 6.3.1-1721805003.877871eb.noble
  • Used Zammad installation type: package
  • Operating system: Ubuntu 24.01 LTS
  • Browser + version: Edge and Chrome

Expected behavior:

Just sending emails via smtp with M365 connector

Actual behavior:

We have a new installation of Zammad on a custom VM.
When we reply to a ticket by email, we very often receive the error “Unable to send email to ‘XXX@XXX.de’: can’t modify frozen String: “execution expired””.
We have connected our system to an M365 channel. Here the connectors are shown as error-free. The health check also shows no errors.
The issue is made more difficult because some emails are delivered correctly.
It is also only about outgoing emails. Incoming emails have worked perfectly so far.
We have already searched all forums (Zammad, GitHub, and others), unfortunately without success.

We have also checked the production.log:

image
image975×513 45.6 KB

Steps to reproduce the behavior:

Just answering a ticket per email.

Maybe someone could help us.

2

Additional information:
When we take a look at the raw data of an email which runs into the frozen string-error, we get an error 500 from zammad.
image

3

Hi @msinistar. Could you please post the log file when this 500er happens?

4

Hi, here is the production.log when the error 500 happens:

image
image1653×573 27.2 KB

5

Is this a vanilla default installation of Zammad or have you installed addons or changed source code of any form?

6

This is a default installation. The only thing we configured was the ssl-Config and the M365 connector.
Yesterday we reinstalled Zammad (from the package) to make sure we didn’t make a mistake. The installation worked without any problems.
But the “Forzen string”-error (and the 500 error) happens after a view tests.

7

The strange thing is that one mail is sent, then the next 2 times it doesn’t work, then it works again and so on.