Auth0 Fails to Display Customized Classic Login MFA Screen During Post-Login Actions

Auth0 fails to display a customized Classic Login Multi-Factor Authentication (MFA) screen when an administrator enforces MFA via a Post-Login Action. This occurs because Auth0 redirects the user to the Universal Login screen instead of the Classic Login template when an Action triggers the MFA prompt. Customize the Universal Login MFA screens via the Auth0 Admin Console, configure the MFA settings to Always or Adaptive, or migrate the application entirely to Universal Login to resolve this issue.

• Auth0
• Classic Login
• Universal Login
• Multi-Factor Authentication (MFA)
• Post-Login Actions

The error occurs because Auth0 redirects the user to the Universal Login screen instead of the Classic Login template when a Post-Login Action triggers the MFA prompt.

To resolve the customization issue, customize the Universal Login MFA screens to match the Classic Login design, adjust the MFA enforcement settings, or migrate the application to Universal Login.

Option 1: Customize the MFA screen for New Universal Login

1. Navigate to the Auth0 Admin Console.
2. Choose Branding and select Universal Login.
3. Customize the Universal Login Multi-Factor Authentication screens to reflect the existing Classic Login customizations.

Option 2: Set MFA factor to Always or Adaptive

1. Choose Security and select Multi-factor Auth.
2. Select Always or Adaptive MFA in the Define policies section to enforce the customized page.
3. Migrate the application authentication flow to Universal Login to ensure consistent branding across all prompts.

Option 3: Migrate to New Universal Login

Before migrating to the New Universal Login, it is recommended to review the Universal Login vs. Classic Login documentation on the differences between the two to identify which features may not be supported.

1. Within the Auth0 Admin Console, navigate to Branding > Universal Login > Manage Classic Login > select Universal Login > save changes.
2. To customize the branding theme of NUL, navigate to Branding > Universal Login > Update Branding Theme.
3. To customize any screens and prompts under NUL, navigate to Branding > Universal Login - Edit Text and Translation.

For further information regarding customizing NUL, please review the Customize Universal Login documentation.