# 31480: Temporarily Unavailable

Log Level: ERROR

## Description

This means the callee is currently unavailable. In the Voice JavaScript SDK changelog, Twilio maps this to `ClientErrors.TemporarilyUnavilable`, and the error dictionary lists it as a Voice `ERROR`.

### Possible causes

* The callee is temporarily unavailable and cannot accept the call.
* Your client cannot reach Twilio's signaling or media infrastructure because DNS, firewall, or edge configuration blocks the required connections. Voice SDKs require both signaling and media connectivity.
* Your network restricts UDP, and you have not provided ICE servers from Twilio Network Traversal Service to establish media connectivity over TURN.

### Possible solutions

* Retry the call after the callee is available again.
* Allow outgoing TCP and UDP traffic from your application to Twilio's signaling and media servers, and make sure your firewall allows return traffic.
* If UDP is restricted, use Twilio Network Traversal Service and pass the returned `ice_servers` or `iceServers` values to your Voice client.
* If you use a restrictive network, choose a specific edge location that matches your deployment so you only need to allow the relevant media server addresses.

#### Additional resources

* [Error and Warning Dictionary](/docs/api/errors)
* [Voice SDK Error Codes](/docs/voice/sdks/error-codes)
* [Voice SDKs Network Connectivity Requirements](/docs/voice/sdks/network-connectivity-requirements)