Teamtalk QT on Windows does not work when VPN with UDP over TCP is in use

[cyrmax]

Description

When some VPN is in use on the system, Teamtalk client starts very slowly, it takes over 10 seconds to open the UI. And after that I cannot connect to any server, encrypted or plain, located in any country. I even cannot connect to my own server so I can be sure that there are no restrictions for my VPN.

VPN itself is self-hosted too and I am sure that there are no restrictions as well.

While connected to the VPN I can connect to any teamtalk server via telnet console and even log in. Other UDP streams also work, for example I can talk in discord, make calls in Telegram and Whatsapp.

Also the problem exists only on the Windows version, on Android with the same VPN I can normally connect to any server and talk there.

Application

• [X] qtTeamTalk
• [ ] TeamTalkAndroid
• [ ] iTeamTalk
• [ ] TeamTalkClassic
• [ ] TeamTalkServer

Platform

• [X] Windows
• [ ] macOS
• [ ] Android
• [ ] iOS
• [ ] Linux

Expected behavior

Teamtalk should work normally as other applications do.

Actual behavior

Teamtalk refuses to connect and hangs in connecting state endlessly without even logging in to a server.

Steps to reproduce problem

1. Install Hiddify next vpn application;
2. Set up or find any vpn with reality protocol;
3. Connect to it in VPN or VPN Service mode enabled in hiddify;
4. Try to open Teamtalk and connect to something

[jeremyp3]

what type of vpn is it?

[cyrmax]

@jeremyp3 It is xtls reality. Xray as a server and hiddify as a client app.