URL_TO_YOUR_ASSET Error when using Auth0 CLI

[auth0.knowledge2]

Overview

This article explains the cause of a login failure and the following error when logging into a custom domain after customizing the Universal Login page.

URL_TO_YOUR_ASSET

Applies To

• Auth0 CLI
• Universal Login
• Advanced Customization

Cause

Starting with the ~1.9.0 version of the Auth0 CLI, after a user logs in using the auth0 login command and runs auth0 universal-login customize, they will be prompted to select a rendering mode for customization: Advanced or Standard.

This issue occurs when a user:

1. Chooses Advanced mode and selects a prompt to customize (e.g., login)
2. Makes no changes and keeps the default settings
3. Later, it is switched to Standard mode to customize the Universal Login
4. Attempts to log in through their custom domain

When this sequence happens, the login page fails to load, and the browser displays a blank page. In the Network tab of the Developer Tools, a 404 error appears for a request to a missing asset URL.

{
 "tenant": "TENANT-NAME",
 "prompt": "login",
 "screen": "login",
 "rendering_mode": "standard",
 "context_configuration": [
  "screen.texts"
 ],
 "default_head_tags_disabled": false,
 "head_tags": [
  {
   "tag": "script",
   "attributes": {
    "src": "URL_TO_YOUR_ASSET",
    "async": true,
    "defer": true,
    "integrity": [
     "ASSET_SHA"
    ]
   }
  },
  {
   "tag": "link",
   "attributes": {
    "rel": "stylesheet",
    "href": "URL_TO_YOUR_ASSET"
   }
  }
 ]
}

Solution

To solve this issue:

1. Switch back to Standard mode by modifying the configuration file that opens in Notepad after running auth0 universal-login customize
2. Delete all other keys inside the JavaScript object in the file
3. Ensure the file contains only:

{
 "rendering_mode": "standard"
}

4. Save and close the file.

After making this change, the Universal Login should work correctly. Avoid selecting Advanced mode unless a specific modification is required.