[sva_]

Sounds to me like it is perhaps a firewall issue?

Also, I remember that MS used to still offer a "Skype for Desktop" native app on windows, additionally to the electron based app. I haven't used Windows/Skype for some time now though, so I'm not sure.

[Yizahi]

No, it started after upgrade to 8.x versions. I've tried to keep 7.x working for as long as could and after MS force banned that branch and I upgraded to electron version (which supposedly was tested for more than a year already) it started to freeze, drop call, delay messages and so on. And multiple people in the office reported this so we started migrating from this thing. And web version doesn't work in Firefox.