Event - accept request of an user missing?

Good evening, 

if I start an event and some users start a request to join this event - an email is sent to me, that there is a request. 

But in notifications, event management and in the event view - there is nothing. I searched the studio action buttons for some "accept" method, but I don't find something. 

- My questions are: 

1. is there something wrong with my installation?

2. do I need an additional modul to run events?

3. is there something to add to a siteblock and it's fixed?

thank you & best regards

Andreas