Hey Denisa,
That feature should definitely still be there in the New Teams client (it was brought back quite a while ago after a temporary removal). Since it worked for you recently, this sounds like a UI glitch or a change in where you are clicking.
Could you clarify a couple of things?
- Are you trying to right-click the person's name from inside the main Chat list (the rail on the left side) or from the top of an open conversation window?
- If you are using a "popped out" chat window, does the option reappear if you close the pop-out and look at the main Teams window?
In the meantime, check if you can still access the list of people you are notifying. Go to Settings > Notifications and activity > People > Manage notifications. Let me know if that menu is still accessible to you.