HTTP 400 when patching /api/v2/branding/templates/universal-login

Problem statement

Receiving 400 error when attempting to patch a New Universal Login Page Template at /api/v2/branding/templates/universal-login

Symptoms

The error may be unhelpful - For example: Data does not match any schemas from 'oneOf'

Cause

This can be caused by placing the auth0:widget in the HEAD, it is required to be in the BODY of the page template.

There is also a size limit on New Universal Login Page Templates, they can not be bigger than 102,400 characters.

Solution

Make sure the auth0:widget is defined in the BODY of the HTML template and verify that the page template is smaller than 102,400 characters.