Used Zammad version: 6.1.0-1695288641.c09272ec.focal
Used Zammad installation type: package
Operating system: Ubuntu 20.04.6
Browser + version: Chrome 118.0.5993.89
Zammad only sends new mail notifications to two agents, ignoring the other 4 agents. Each user is configured the same and is assigned to the Support Group.
Mail account and notifications are configured.
Maybe your agents only disabled notifications via personal preferences (/#profile/notifications).
You could try to switch via Admin → User and check their preferences.
It’s highly unlikely that notifications don’t work in zammad. There are no open issues about it at the moment and I am not aware of any recent notification changes.
I was able to solve my problem. Every time someone opened a ticket, the notification system tried to send out emails. And one of our agents decided to use a wrong email address that did not exist.
After fixing this, mail notifications go out without any problems. I think Zammad should still notify the other agents, even though one of the addresses wasn’t correct.