---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/13111#article
headline: "13111: Annotate: Annotate must contain only one of element X"
url: https://www.twilio.com/docs/api/errors/13111
inLanguage: en
dateModified: 2026-06-08T11:38:30.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 13111: Annotate: Annotate must contain only one of element X

Log Level: ERROR

## Description

This error occurs when Twilio processes an `<Annotate>` instruction that contains more than one instance of a nested element that is allowed only once.

### Possible causes

* The `<Annotate>` block includes the same child element more than once.
* Your application generated duplicate annotation elements while building TwiML dynamically.
* Two XML fragments were combined into a single `<Annotate>` block and created a duplicate child element.

### Possible solutions

* Review the `<Annotate>` block and keep only one instance of each supported child element.
* Inspect the final TwiML returned by your application and remove any duplicate nested elements before sending it to Twilio.
* If you generate TwiML with templates or helper code, update that logic so each annotation field is added only once.

#### Additional resources

* [TwiML for Programmable Voice](/docs/voice/twiml)
* [Voice Insights overview](/docs/voice/voice-insights)
* [Call Annotation Resource](/docs/voice/voice-insights/api/call/call-annotation-resource)