---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/520013#article
headline: "520013: Identifier formatting error"
url: https://www.twilio.com/docs/api/errors/520013
inLanguage: en
dateModified: 2026-04-01T03:32:01.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 520013: Identifier formatting error

Log Type: TWILIO

Log Level: WARNING

## Description

Identifier was added but does not strictly align with the expected schema pattern.

### Possible causes

* Identifier value does not follow the recognized pattern (e.g., missing an @ symbol in an email address)

### Possible solutions

* Validate the identifier string against backend or local regular expressions prior to submission to ensure formatting consistency