Hello,
We have this problem. When a ticket is created, technicians or sequesters don't receive a mail notification for this. The only way it is working is when requester creates a ticket and they reply to it, then the requester who created the ticket receives a notifications only for the reply not for the created a ticket. When we stop/start the ServiceDesk service the mail notifications are starting to work again, but the mails who arrive are from past days and this stops working after about 10-20 minutes