Error 409 "device_account_conflict" with MFA

Hi there, for our project we have 3 allowed provider: Google, Apple and Auth0. We also want to add an account confirmation through sms at the first login so we planned to:

  • add a rule to force MFA enrollment if the user has none;
  • setup Auth0 with our Twillio account;
  • customize MFA page to our layouts (html + js).

The first 2 points were easy and straightforward, now we are facing an issue with the Auth0 Guardian.js library.
In particular after typing the phone number and calling the .enroll method. We get the following error:

{“statusCode”:409,“error”:“Conflict”,“message”:“This flow only supports enrolling one single authenticator. You can use the /mfa/associate endpoint to enroll another one.”,“errorCode”:“device_account_conflict”}

I can’t find any info about the /mfa/associate route but after several tests with multiple accounts I think there is something wrong when enrolling with the same email address but with multiple providers but I’m not 100% sure.
Also we have the same error if we use the Auth0 default templates with “classic experience” interface but everything works fine if we use the new version.

Thanks for your help.

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