---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/13112#article
headline: "13112: Annotate: Invalid nested element"
url: https://www.twilio.com/docs/api/errors/13112
inLanguage: en
dateModified: 2026-06-08T11:38:30.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 13112: Annotate: Invalid nested element

Log Level: WARNING

## Description

This warning is raised when `<Annotate>` contains a nested element other than `BillingReferenceTag`. Use only `BillingReferenceTag` inside `<Annotate>`.

### Possible causes

* Your TwiML nests an unsupported child element inside `<Annotate>` instead of `BillingReferenceTag`.
* The nested element name is misspelled or uses incorrect casing. TwiML element names are case sensitive.
* Your application generates TwiML dynamically and inserts extra XML elements that `<Annotate>` does not support, because Twilio only accepts specific TwiML verbs and nouns during parsing.

### Possible solutions

* Update your TwiML so `<Annotate>` contains only `BillingReferenceTag`.
* Remove any other nested TwiML or custom XML elements from `<Annotate>`.
* Verify the spelling and casing of `BillingReferenceTag` before you return the TwiML response.
* Generate your TwiML with a Twilio helper library when possible. This can help you avoid invalid XML structure.

#### Additional resources

* [TwiML for Programmable Voice](/docs/voice/twiml)
* [Programmable Voice API Overview](/docs/voice/api)
* [Troubleshooting Twilio](/docs/usage/troubleshooting)