---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/51005#article
headline: "51005: Client Connection: Command or keepalive acknowledgement not received"
url: https://www.twilio.com/docs/api/errors/51005
inLanguage: en
dateModified: 2026-06-09T11:00:42.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 51005: Client Connection: Command or keepalive acknowledgement not received

Log Level: ERROR

## Description

Twilio dropped the client connection because the client did not acknowledge a command or a keepalive message within the expected time. This usually indicates an interrupted or unstable network connection between the client SDK and Twilio.

### Possible causes

* The device lost network connectivity or switched between networks while the connection was active.
* High latency or packet loss prevented the client from responding to Twilio in time.
* The application was suspended in the background and could not process keepalive messages.
* A proxy, firewall, or other network control interrupted the persistent connection used by the SDK.
* The client application was overloaded or blocked and could not send the required acknowledgement.

### Possible solutions

* Check whether the device has a stable internet connection and test again on a reliable network.
* Make sure your application does not block the main thread or otherwise prevent the SDK from processing incoming messages.
* If your app runs on mobile devices, review background execution behavior to confirm the SDK can maintain or restore connectivity as expected.
* Verify that firewalls, proxies, or network security tools allow persistent client connections.
* Let the Twilio SDK reconnect automatically when possible and handle reconnection events in your application so the user can recover gracefully.
* If this error happens frequently, capture client-side network logs and SDK logs to identify connectivity interruptions or timeouts.

#### Additional resources

* [Twilio Chat documentation](/docs/chat)
* [Twilio Sync documentation](/docs/sync)