# 63106: phone\_number is not a RCS capable number

Log Type: APPLICATION

Log Level: ERROR

## Description

Twilio returns this error when the `phone_number` you supplied is not RCS capable. RCS Business Messaging uses a branded sender profile rather than a traditional phone number, and RCS is compatible with Android devices and iOS devices running iOS 18 or later.

### Possible causes

* The recipient device or carrier does not support RCS, so Twilio cannot use that number for an RCS delivery. Twilio attempts RCS first only when the destination is RCS-capable, and it falls back to SMS when RCS is unavailable.
* You are trying to use a Twilio number as an RCS test device. Twilio numbers cannot be used as RCS test devices.
* The RCS sender has not been approved for messaging to that number yet. Before you message phone numbers that are not added as test devices, carrier approval is required.

### Possible solutions

* Send to a number tied to an RCS-capable device. Twilio supports RCS on Android devices and iOS
  devices running iOS 18 or later.
* Add the destination as a test device during RCS onboarding, or test with an Android device that you allowlist for onboarding.
* Configure RCS plus SMS fallback with a Sender Pool when you want Twilio to deliver via RCS first and switch to SMS when RCS is unavailable.

#### Additional resources

* [RCS Business Messaging](/docs/rcs)
* [Get started with branded RCS messaging](/docs/rcs/onboarding)
* [Channel Fallback](/docs/comms/channel-fallback)