In China I use the Zoiper can not call Chinese number, no voice , although I use VPN can not call.Please tell me how to set up the software Proxy server thank you.
The chineese government blocks the VoIP communications and some VPNs that allow them. You should first verify if your VPN allows VOIP. Then you can try to follow our article regarding one-way or missing audio: https://www.zoiper.com/en/support/home/article/14/Missing_or_one_way_audio