# 19011: Contact update failed: invalid JSON or non-updatable field

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when your contact update request contains invalid JSON or includes fields that this endpoint does not allow you to update. Update only `first_name`, `middle_name`, `last_name`, `legal_name`, `preferred_name`, `unique_customer_provided_id`, or `custom_fields`.

### Possible causes

* The request body is not valid JSON.
* The request includes one or more fields other than `first_name`, `middle_name`, `last_name`, `legal_name`, `preferred_name`, `unique_customer_provided_id`, or `custom_fields`.
* The request mixes supported update fields with unsupported fields in the same payload.

### Possible solutions

* Validate the request body and send well-formed JSON.
* Remove any unsupported fields from the update request.
* Limit contact updates to `first_name`, `middle_name`, `last_name`, `legal_name`, `preferred_name`, `unique_customer_provided_id`, and `custom_fields`.
* Retry the request after you correct the payload.

#### Additional resources

* [Contact API](/docs/messaging/features/contact-api)
* [Compliance Toolkit for Programmable Messaging](/docs/messaging/features/compliance-toolkit)
* [Debugging your Twilio application](/docs/usage/troubleshooting/debugging-your-application)