Recover audio and video chat on Viber on Bluestacks 4 on Windows 7?

I use Viber on my Android emulator Bluestacks 4 on Windows 7 Pro. I do not have a smartphone. To date, I have been able to use Viber to chat with my contacts about text and also to chat with them via audio and video (in the latter case with my webcam). Today I uninstalled Viber by mistake. I then reinstalled it, and since then I could only chat with text. When I call them, they can not answer the call. When they try to call me, I can see them calling, but if I click on the green phone icon, nothing happens.

How can I restore the audio chatting and video chatting feature?