SIP duplicate INVITE / 482 Request merged when ws_url changed from localhost to domain (separating SIP from LiveKit server)

[ashusatp]

Hi team,

I am trying to separate my SIP service from the LiveKit server, but I am encountering a duplicate SIP request issue when the SIP server connects to LiveKit using a domain instead of localhost.

Previously, everything worked correctly when all services were running on the same instance.

Previous Setup (Working)

All services were running on the same server:

• LiveKit
• Redis
• SIP

The SIP service was connecting to LiveKit locally:

ws_url: ws://localhost:7880

In this configuration, outbound calls worked perfectly and no SIP errors occurred.

New Setup (Distributed Deployment)

I am now trying to separate the services across multiple servers.

Architecture:

Server 1
  LiveKit Server

Server 2
  SIP Server

Server 3
  Redis

Since SIP is now running on a different machine, I updated the configuration to use the LiveKit domain:

ws_url: wss://livekit.my-domain.com

However, after making this change, outbound calls started failing.

Error

When creating a SIP participant, I receive the following error:

Error creating SIP participant: TwirpError(code=internal, message=twirp error unknown: unexpected status from INVITE response: sip status: 482: Request merged, status=500, metadata={'error_details': 'CA0SR3VuZXhwZWN0ZWQgc3RhdHVzIGZyb20gSU5WSVRFIHJlc3BvbnNlOiBzaXAgc3RhdHVzOiA0ODI6IFJlcXVlc3QgbWVyZ2VkGjwKJXR5cGUuZ29vZ2xlYXBpcy5jb20vbGl2ZWtpdC5TSVBTdGF0dXMSEwjiAxIOUmVxdWVzdCBtZXJnZWQ=', 'sip_status': 'Request merged', 'sip_status_code': '482'})

Full log excerpt:

Error creating SIP participant: TwirpError(code=internal, message=twirp error unknown: unexpected status from INVITE response: sip status: 482: Request merged, status=500) | [room=outbound-agent-GYXPwtHb7lQxjXPRmXUqbJYsHA-125d7e2bf589407387a85b232633a10f_+9172890080554]

Observed Behavior

From the SIP logs it appears that multiple INVITE requests are being triggered for the same call, which causes the SIP provider to return:

482 Request merged

This only happens when the SIP server connects to LiveKit via the domain (wss://...). When using localhost and all the services on one instance, everything works correctly.

What I Am Trying To Achieve

I want to run the components separately for scalability:

• LiveKit Server
• SIP Service
• Redis

All on different machines.

However, after separating them, I am unable to make outbound SIP calls successfully.

Questions

Is this architecture supported?

LiveKit Server  → Server A
SIP Service     → Server B
Redis           → Server C

Are there any additional configurations required when SIP connects to LiveKit using a domain instead of localhost?

Could this issue be related to WebSocket signaling timing or SIP participant creation retries?

Environment

LiveKit version: latest
SIP image: livekit/sip:latest
Deployment: Docker

If there are any recommended configurations for running SIP and LiveKit on separate machines, I would really appreciate the guidance.