New tickets sometimes get old ticket numbers

Technical assistance
1

Hello Zammad Community,
we have a weird problem since the 31st of January, i haven’t found a solution yet.
It doesn’t happen all the time and we can’t reproduce it.

Infos:

  • Used Zammad version: 6.4.1-1739528949.22a0b20a.centos9
  • Used Zammad installation type: package
  • Operating system: RHEL 9.5
  • Browser + version: Edge 133.0.3065.69

Expected behavior:

Customer sends an Email to our support-email:

  • Customer get a automated answer email
  • a new ticket is opened
  • admins get an info email: “a new ticket has been created by User”
    • ticket number in subject line
    • link to ticket in zammad

Actual behavior:

Customer sends an Email to our support-email:

  1. Sometimes it only sends the info email to the admins and did not create a new ticket in Zammad

    • in this case: The info mail always has an older ticket number in the subject line
    • the link is always to an old ticket
    • the “old” ticket does not contain any information about the new ticket

  2. Sometimes when a customer replies to a ticket, only an info mail is sent to the admins

    • in this case: The info mail suddenly has two ticket numbers (the number of the original ticket and a number of an older ticket)
    • the link in the email leads to the ticket with the old number
    • there is no information about the answer in the “old” and original ticket

  3. Sometimes it creates a new ticket in Zammad, but sends two info emails

    • in this case: One ticket with a new ticket number and the other with an old ticket number
2

We found the Problem.

The Service was moved to a new VM and was deactivated.
Somehow the Service on the old VM activated it self again.