Zoom phone on Android NOT displaying income calls

[BC2086]

I have Zoom phone, using Android Samsung Galaxy 10. When a call comes in, it plays the ring tone but does NOT display an answer screen where I can accept or decline the call. I literally have to scroll to my Zoom icon and click it to display the answer screen. How do I correct this?

Also, on different but similar note, is there a way to (1) set ringtone to "mute" (so it doesn't audibly ring, but still display the answer screen, and (2) is there a way to set Zoom phone to NOT ring at all on mobile device and only ring on my VOIP handset?