# 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.