VOIP call (TURN) won't work with Synapse

[okias]

Description

I did configured TURN according https://github.com/matrix-org/synapse/blob/master/docs/turn-howto.md but sadly no connection between calling clients is created.

Steps to reproduce

• configure & start coturn
• open firewall ports & apply
• restart matrix

2020-06-19 17:38:29,787 - twisted - 192 - INFO -  - Timing out client: IPv4Address(type='TCP', host='127.0.0.1', port=60488)

occasionally is something like that printed into log, which matches TURN UDP IP range

configuration

turn_uris: [ "turns:turn._our_server_dot_com:3478?transport=udp" ]
turn_shared_secret: "XXXXXXXXXXXXXXXXXXXXX"
turn_user_lifetime: 86400000
turn_allow_guests: true

Version information

• our homeserver:

{
    "python_version": "3.6.10",
    "server_version": "1.15.0"
}

• Install method: pip

• Platform: Gentoo

That's generally all info I know, since I tried to debug it, but sadly I'm not much skilled in STUN/TURN etc. + haven't found much debugging approaches ref. #1519

[clokep]

I'd suggest asking in #synapse:matrix.org to see if anyone can help debug your STUN/TURN setup.