Some technicians don't receive notifications when a task is assigned to a support group.

If a request is assigned to a support group the notification works and when a task is assigned to a single user too.

I can't see differences between technicians with or without this notification problem and the problem isn't only for emails. Even notification bell doesn't notify new task assigned.

In the same support group notification works for some users and if I move these technicians with notification problemi to a different support group the problem remains for the same technicians.

I think there is something in users/technicians profile doesn't work.

Is there any other setting to check?