---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/32209#article
headline: "32209: SIP: Secure transport required"
url: https://www.twilio.com/docs/api/errors/32209
inLanguage: en
dateModified: 2026-03-11T20:01:16.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 32209: SIP: Secure transport required

Log Type: APPLICATION

Log Level: ERROR

## Description

When secure calling is enabled, Twilio cannot accept calls made using UDP or TCP. Please use TLS.

### Possible causes

* Media security is enabled on your SIP domain or trunk, but Twilio received SIP traffic over an insecure protocol, such as UDP or TCP.
* You are using SIP registration, and are attempting to place a secure call to an endpoint where all of the available bindings were registered with an insecure protocol, such as UDP or TCP.

### Possible solutions

* Please ensure your PBX or end device is configured to send SIP traffic over the TLS transport.
* If you are using SIP registration, your device must be configured to *register* over the TLS protocol. Devices registered over insecure protocols will not be attempted for secure calls.