# 21910: Invalid 'From' and 'To' pair. 'From' and 'To' should be of the same channel

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when you send a Message resource request where `From` and `To` use different channel address formats. Twilio requires channel-specific addressing, such as an `E.164` phone number for SMS or MMS and `whatsapp:+15558675310` for WhatsApp.

### Possible causes

* You sent from an SMS or MMS sender in `E.164` format, but the destination is a WhatsApp address such as `whatsapp:+15558675310`.
* You sent from a WhatsApp-enabled sender, but the destination is a plain phone number instead of a WhatsApp address with the `whatsapp:` prefix.
* One of the channel addresses is formatted incorrectly for the channel you intend to use. For WhatsApp, both sender and recipient addresses must include the `whatsapp:` prefix.

### Possible solutions

* Make sure `From` and `To` are on the same channel before you send the request. For SMS or MMS, use phone numbers in `E.164` format for both values.
* For WhatsApp, set `From` to your approved WhatsApp sender address and set `To` to the recipient's WhatsApp address. Prefix both values with `whatsapp:`.
* Verify that the `From` value belongs to your Twilio account and is valid for the channel you are using. Twilio only accepts a `from` sender that is hosted within Twilio and belongs to the account creating the message.
* If you send with `MessagingServiceSid`, omit `From` so Twilio can select a sender from the Messaging Service's Sender Pool. For channel destinations such as WhatsApp, add a sender for that same channel to the Messaging Service.

#### Additional resources

* [Twilio Messaging Channels](/docs/messaging/channels)
* [Messages resource](/docs/messaging/api/message-resource)
* [Quickstart: Send and receive WhatsApp messages](/docs/whatsapp/quickstart)