I am not sure if it is packet loss however, I have one user that when he logs in the roster does not show. The backend shows his session going and he shows as online in Spark but the roster never appears(everyone shows offline). Also, when he is logged in no other user sees him online either. When I tried logging in on another computer I log in sucessfully and I can see all the users. I have tried both Pandion and Spark for the frontend.