If I get a call and accept it, the line will still ring. This disturbs the phone call enormously. Where can you turn it off?
The issue has the same cause as the one described here: https://www.zoiper.com/en/support/home/article/72/calls_get_disconnected_after_30_seconds#windows
The call get not disconnected. It rings during the call
Yes, but this is caused from the same thing that is described at the F.A.Q. section.
The only difference for you is that the server keeps sending the ringing since the confirmation message has not reached it.