Voice calls are not working under "antizapret" VPN then using "gray" IPs (like 192.168.X.X). Antizapret is a free VPN service used by people in Russia to bypass censorship. Its OpenVPN configuration file: https://antizapret.prostovpn.org/antizapret-tcp.ovpn
Antizapret support suggests that the bug is most likely related to determining the IP address for penetrating NAT — perhaps Telegram developers believed that when a VPN connection is established, all traffic always goes through it, which is not true in the case of this service: https://ntc.party/t/telegram-vpn/2852
Steps to reproduce
Connect to the Internet using "gray" IP (like 192.168.X.X)
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