Facetime unavailable on 2019 MacBook Air
Hi.
I am trying to figure out why my sister's 2019 MacBook Air sends the message "FaceTime Unavailable" when she tries to use FaceTime, and when anyone else tries to FaceTime with her.
Here are the specs: MBA 13.3 SG/1.6 GHZ/8GB/128 GB - USA.
It's running macOS 10.15 Catalina.
FaceTime worked on this device until mid-April and then something went wrong. When she attempts to use it now, each attempt creates another copy of FaceTime in Applications (i.e. FaceTime(2), FaceTime(3), etc..)
I have looked at the Apple "If FaceTime Isn't Working on your Mac" page and see no solution there. The camera is working, she is in an area that allows FaceTime, she has adequate Wi-Fi service.
I don't see any questions on here about similar issues that are not many years old or relating to different devices.
Can anyone please suggest how to fix this? Thanks very much in advance.
MacBook