# 63108: Sender is not ready to add test device

Log Type: CARRIER

Log Level: ERROR

## Description

Twilio returns this error when you try to add a test device to an RCS sender before the sender finishes getting ready in the Twilio Console. In the RCS onboarding flow, create the sender first, then use Add device to test this sender to invite a number in `E.164` format.

### Possible causes

* Twilio is still preparing the sender after creation or a recent update. The error tells you to wait briefly and try again, which points to a temporary readiness state.
* The sender setup is not complete yet. Twilio requires you to finish the RCS sender setup before you can test it.

### Possible solutions

* Wait briefly, then try the action again.
* Complete the RCS sender setup in the Console before you add a test device.
* When you add the test device, enter a phone number in `E.164` format and accept the tester invitation on the device. Use a device and carrier that support RCS.

#### Additional resources

* [Get started with branded RCS messaging](/docs/rcs/onboarding)
* [Send and receive RCS messages](/docs/rcs/send-an-rcs-message)
* [Use RCS messaging with Studio](/docs/studio/tutorials/use-rcs-with-studio)