---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/80911#article
headline: "80911: Call To Message Only Session Rejected"
url: https://www.twilio.com/docs/api/errors/80911
inLanguage: en
dateModified: 2026-06-08T12:04:59.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 80911: Call To Message Only Session Rejected

Log Level: WARNING

## Description

Twilio returns this warning when an inbound voice call reaches a Proxy Session whose `mode` is `message-only`. Proxy Sessions can use `message-only`, `voice-only`, or `voice-and-message`. A `message-only` session does not accept voice traffic, so Proxy rejects the call.

### Possible causes

* Your application created the Session with `mode` set to `message-only`.
* An out-of-session callback created the Session in `message-only` mode, and a participant then placed a call to the Proxy number.
* The Twilio phone number assigned to the Proxy workflow is still routing inbound voice traffic to Proxy through its voice configuration, even though the session is intended for messaging only.
* The Proxy number pool or workflow was set up for SMS use, but callers are also using the same number for voice.

### Possible solutions

* If participants need to call each other, create the Session with `mode` set to `voice-and-message` or `voice-only`.
* If you auto-create Sessions from an out-of-session callback, return session data with a voice-capable `mode` when you expect calls.
* If the workflow should stay SMS-only, update the Twilio phone number's voice configuration so inbound calls go to your own `voice_url` or voice application instead of Proxy.
* Use Twilio phone numbers with the capabilities required for your workflow. If you need masked calls, make sure the numbers in your Proxy pool support inbound voice.

#### Additional resources

* [Proxy Session resource](/docs/proxy/api/session)
* [Proxy Quickstart](/docs/proxy/quickstart)
* [IncomingPhoneNumber resource](/docs/phone-numbers/api/incomingphonenumber-resource)