Voice call PC to PC

Hi all,

We have spark 2.5.7 installed. When I begin a chat with another user, I have “Voice Call” button available, but I can´t begin a voice call (PC to PC) with other users. I get this message: The session was rejected.

Other users do not have “Voice Call” Button…

What is wrong? We have all the same spark version…

Thanks in advance,

JJ.-

We have resolved uninstalling spark and installing it again, but with .exe installr, not msi installer…