Auth0 Generates a "too_many_sms_per_tenant" Error When Using a Custom Phone Provider

Auth0 generates an error when the configuration inadvertently uses Auth0 as the Short Message Service (SMS) provider rather than the configured custom provider. This occurs because Auth0 enforces a hard cap of 100 SMS messages per tenant when acting as the default provider. Enabling the Unified Phone Experience in the advanced tenant settings or via an Application Programming Interface (API) request resolves the issue. When the tenant exceeds the limit, Auth0 generates the following error:

too_many_sms_per_tenant

The error will also have the following message:

SMS per tenant rate exceed

• Auth0
• Short Message Service (SMS)
• Multi-Factor Authentication (MFA)

This error occurs when the tenant does not use the Unified Phone Experience, causing Auth0 to act as the default SMS provider rather than the custom phone provider that is configured. Auth0 enforces a hard limit of 100 SMS messages when acting as the default provider. Once the tenant reaches this limit, Auth0 generates the error messages.

What steps enable the Unified Phone Experience via the Auth0 Dashboard?

Enable the Unified Phone Experience toggle in the advanced tenant settings by following these steps.

1. Navigate to the Advanced tenant settings in the Auth0 Dashboard.
2. Locate and enable the Unified Phone Experience toggle.

Enable the Unified Phone Experience Using an API Request

Update the tenant settings by making a PATCH request to the management API with the phone_consolidated_experience flag set to true.

curl --request PATCH \
  --url https://<auth_domain>/api/v2/tenants/settings \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  { "phone_consolidated_experience": true }
}
'

What additional configuration do older tenants require?

NOTE: The following information can be ignored if the Use Tenant-Level Messaging Provider toggle under the Phone Message screen in Multi-factor Authenticate is not visible, as displayed in this screenshot.

Enable the tenant-level messaging provider toggle in the multi-factor authentication settings for older tenants by following these steps:

1. Navigate to Multi-factor Authentication.
2. Select Phone Message.
3. Enable the Use Tenant-Level Messaging Provider toggle.

Ensure a custom phone provider is configured under:

1. Navigate to Branding.
2. Select Phone Provider.
3. If a custom phone provider is used, ensure Custom is selected and that the Provider Configuration section is filled out.