I Skype video call my contact (he has win 10, I have 7) but it tells me "not available, leave message". It does ring once on his end but he can't answer. Our versions (desktop) are up to date. He hears the one ring and calls me back - we then connect OK. HIs settings (notifications, etc.) appear to be correct.
He was previously using the mobile version on his desktop PC and we thought that was the problem. But he deleted or uninstalled the mobile and now uses the desktop version. The desktop version was already installed so he tried using that but still no more than the one ring. It is up to date and I think (not positive) he reinstalled it to see if that might help. But no luck.
System Configuration: Windows / Internet Explorer 11.0
I have also encountered the same type of problem in skype which is causing a problem in video calling and then I found REMOVED FOR SPAM where I got proper help which also in the case helped me a lot, but I dont understand it, so I cannot describe to you what I did to fix it!!!