I'm using this app for work. It is extremely temperamental on my Note9. Lately it either doesn't ring at all but give a missed call notification. The call won't transfer to one of the various lines on the system. The other issue is the call taking over 20seconds to connect on my end when I initiate a call. It's really unfortunate that it's so buggy. I'd suggest uninstalling when not in use. This app has the residual affect of screwing up the normal function of the volume on the phone.