Alerts not working

Alerts not working

Hello there,
I am trying to set up some email alerts and they do not seem to work. At the moment I have 4 custom alerts that will notify DS when mentioned in a ticket comment, when a comment is added, when a ticket is assigned and when a customer replies. 

Even though I created the 4 custom alerts it seems that none of them work and I do not understand why. 

Can someone please help? I have attached some screenshots of what I have created. 

Many thanks,
David