---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/60420#article
headline: "60420: Invalid Contact ID format"
url: https://www.twilio.com/docs/api/errors/60420
inLanguage: en
dateModified: 2026-06-08T12:04:59.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 60420: Invalid Contact ID format

Log Type: APPLICATION

Log Level: ERROR

## Description

Twilio returns this error when your Verify request includes a Contact ID that Twilio cannot parse. In Verify Passkeys, a user is represented as an `Entity`, and Twilio recommends using an immutable identifier such as a system UUID, GUID, or SID for the `identity` value. That `identity` should be 8 to 64 characters long and contain only dash-separated alphanumeric characters. If you send a Passkeys `response.userHandle`, it must be a Base64-encoded, URL-safe contact ID.

### Possible causes

* The Contact ID or `identity` value contains characters that do not match the allowed format for Verify `Entity` identifiers.
* The Contact ID is too short or too long for the Verify `Entity` identifier requirements.
* The `identity` value changed between Passkeys factor creation and later requests, such as challenge creation. Twilio expects you to use the same `identity` value when you create a Passkeys challenge.
* The Passkeys `response.userHandle` value is not Base64-encoded and URL-safe.

### Possible solutions

* Generate an immutable, non-PII identifier in your system, such as a UUID, GUID, or SID, and use that value consistently as the user's `identity`.
* Validate the Contact ID before you send the request. For Verify `Entity` identifiers, keep the value between 8 and 64 characters and use only dash-separated alphanumeric characters.
* Store the `identity` value you used when you created the Passkeys factor, then reuse that exact value in later Verify requests for the same user.
* If you send `response.userHandle` in a Passkeys flow, pass it exactly as returned by the authenticator and do not manually reformat or re-encode it.

#### Additional resources

* [Verify Passkeys quickstart](/docs/verify/quickstarts/passkeys)
* [Entity Resource](/docs/verify/api/entity)
* [Passkeys Factor Resource](/docs/verify/api/passkeys-factor)