> ## Documentation Index
> Fetch the complete documentation index at: https://docs.wejam.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Call Connection Issues

> Fix voice calls that fail to start or drop immediately on corporate networks - connectivity checker, network requirements, and domain whitelisting for voice interactions.

If you can log in and use Jam Assistant but **voice calls won't start** - or the call connects for a few seconds and then ends automatically - the most likely cause is that your corporate network blocks the WebRTC connection used for real-time voice. This page explains how to diagnose and fix it.

<Note>
  Run the built-in connectivity checker first:
  [app.wejam.ai/check](https://app.wejam.ai/check). **Microphone access** is
  required for a full test.
</Note>

## Symptoms

* You can log in and use text chat normally.
* Tapping the voice button fails immediately, or the call ends itself within a few seconds with an error such as *"could not establish connection"*.
* The problem is consistent - it happens every time, not just occasionally.

## Likely cause

WebRTC voice traffic is not allowed on your company network, or the network blocks the signaling connection that starts the call.

## Background: how Jam Assistant uses the network

To load and use text chat, only **TCP port 443** (HTTPS) is required. To create low-latency voice-to-voice interactions, Jam Assistant uses **WebRTC** through the **ElevenLabs EU residency** network. The browser must be able to complete WebRTC signaling on TCP/443 and send media traffic over UDP.

* **ElevenLabs** powers the real-time voice AI. Jam Assistant connects to the ElevenLabs EU residency region for voice calls.
* Signaling uses HTTPS/WebSocket traffic on **TCP/443**.
* Real-time media uses **WebRTC UDP traffic**, including the standard dynamic UDP port range **49152-65535**. Restricting UDP to only `40000-49999` can prevent calls from starting.

## Debugging steps

1. **Run the connectivity checker.** Direct the user to [app.wejam.ai/check](https://app.wejam.ai/check) (microphone access required). This tests the connection end-to-end and reports whether it's the WebRTC/media path or the signaling path that's blocked.
2. **Whitelist the required domains and ports** on the corporate firewall or proxy:

| Domain                                   | Protocol / Port                              | Purpose                         |
| ---------------------------------------- | -------------------------------------------- | ------------------------------- |
| `link.wejam.ai`                          | HTTPS, TCP/443                               | Jam Assistant web app           |
| `app.wejam.ai`                           | HTTPS, TCP/443                               | Connectivity checker (`/check`) |
| `api.wejam.ai`                           | HTTPS, TCP/443                               | REST API                        |
| `eu.residency.elevenlabs.io`             | HTTPS/WSS, TCP/443; WebRTC UDP `49152-65535` | ElevenLabs EU residency service |
| `rtc.eu.residency.elevenlabs.io`         | HTTPS/WSS, TCP/443; WebRTC UDP `49152-65535` | ElevenLabs WebRTC media         |
| `livekit.rtc.eu.residency.elevenlabs.io` | WSS, TCP/443; WebRTC UDP `49152-65535`       | ElevenLabs SDK WebRTC media     |
| `api.eu.residency.elevenlabs.io`         | HTTPS/WSS, TCP/443                           | ElevenLabs API/signaling        |

<Warning>
  For ElevenLabs domains, the firewall must allow WebSocket upgrades on TCP/443
  and WebRTC media traffic over UDP. Blocking either the signaling connection or
  the UDP media path can make a voice call fail before it starts, or end it a
  few seconds after connecting.
</Warning>

## Network requirements (for IT teams)

Jam Assistant's voice calls use low-latency WebRTC connections, facilitated through ElevenLabs EU residency infrastructure. To ensure reliable operation, the following must be supported in the customer's network environment:

**Port accessibility**

* **TCP port 443** is required for HTTPS and WebSocket signaling.
* **UDP ports 49152-65535** must be allowed for WebRTC media traffic to ElevenLabs. This is the standard dynamic UDP port range used by WebRTC; observed calls may use ports such as `50674` or `53396`.

**Domain whitelisting**

* `link.wejam.ai` - Jam Assistant web app
* `app.wejam.ai` - Connectivity checker (`/check`)
* `api.wejam.ai` - REST API
* `eu.residency.elevenlabs.io` - ElevenLabs EU residency service
* `rtc.eu.residency.elevenlabs.io` - ElevenLabs WebRTC media
* `livekit.rtc.eu.residency.elevenlabs.io` - ElevenLabs SDK WebRTC media
* `api.eu.residency.elevenlabs.io` - ElevenLabs API/signaling

Prefer FQDN-based allowlisting for ElevenLabs. Their infrastructure can resolve to changing IP addresses, so IP-only allowlists are more likely to break.

**Corporate network considerations**

Restrictive network environments, such as those common in corporate settings, may impede WebRTC connectivity. In those cases the customer is responsible for ensuring the network supports the required configuration, including allowing the domains above, WebSocket upgrades on TCP/443, and UDP media traffic in the dynamic port range.

**Diagnostic tool**

Use the built-in connectivity checker at [app.wejam.ai/check](https://app.wejam.ai/check) to diagnose connectivity issues. The page checks microphone access, the JAM API connection, an ElevenLabs WebRTC connection, and a short voice test through an echo agent. Microphone access is required for a full test.

## Related articles

* [Voice Calls](/external/assistant/voice-calls) - how a normal call works, including other troubleshooting tips
* [Frequently Asked Questions](/external/coach/help-and-reference/faq) - including microphone and audio troubleshooting

***

*Last updated: August 2026*