Redirect loop and Failed Exchange error

[warren.harrison]

I am in the process of testing a new Auth0 Tenant with Universal Login enabled with the goal of migrating our current application that uses a tenant with the Classic Login enabled. I have set up a custom domain and updated our app code to send the audience parameter when requesting access tokens (as explained in Configure Features to Use Custom Domains).

Login works as expected, most of the time. Sporadically, when logging in via the new tenant, I get stuck in a redirect loop in the browser. When this happens, looking at the Auth0 logs, I see a “Failed Exchange” error, with the data below, even though I am sending the tenant domain name as the audience.

It’s not clear to me why this is happening, even less why it’s not consistent.

Any help is much appreciated.

{
  "date": "2025-03-05T13:13:14.091Z",
  "type": "feccft",
  "description": "Service not enabled within domain: https://dev-auth.frac.at/api/v2/",
  "connection_id": "",
  "client_id": "xxxxxxxxxxxxxxxxxxx",
  "client_name": "Fractured Atlas",
  "ip": "192.24.155.116",
  "client_ip": "192.24.155.116",
  "user_agent": "Other 0.0.0 / Other 0.0.0",
  "hostname": "dev-auth.frac.at",
  "user_id": "",
  "user_name": "",
  "audience": "https://dev-auth.frac.at/api/v2/",
  "scope": null,
  "auth0_client": {
    "name": "ruby-auth0",
    "version": "5.18.0",
    "env": {
      "ruby": "3.4.1",
      "rails": "8.0.1"
    }
  },
  "$event_schema": {
    "version": "1.0.0"
  },
  "log_id": "90020250305131314410970000000000000001223372069716678222",
  "tenant_name": "fa-development",
  "_id": "90020250305131314410970000000000000001223372069716678222",
  "isMobile": false,
  "originalData": {
    "date": "2025-03-05T13:13:14.091Z",
    "type": "feccft",
    "description": "Service not enabled within domain: https://dev-auth.frac.at/api/v2/",
    "connection_id": "",
    "client_id": "xxxxxxxxxxxxxxxxxxx",
    "client_name": "Fractured Atlas",
    "ip": "192.24.155.116",
    "client_ip": "192.24.155.116",
    "user_agent": "Other 0.0.0 / Other 0.0.0",
    "hostname": "dev-auth.frac.at",
    "user_id": "",
    "user_name": "",
    "audience": "https://dev-auth.frac.at/api/v2/",
    "scope": null,
    "auth0_client": {
      "name": "ruby-auth0",
      "version": "5.18.0",
      "env": {
        "ruby": "3.4.1",
        "rails": "8.0.1"
      }
    },
    "$event_schema": {
      "version": "1.0.0"
    },
    "log_id": "90020250305131314410970000000000000001223372069716678222",
    "tenant_name": "fa-development",
    "_id": "90020250305131314410970000000000000001223372069716678222",
    "isMobile": false
  },
  "integrityRuleset": {},
  "id": "90020250305131314410970000000000000001223372069716678222"
}

[vlad.murarasu]

Hi @warren.harrison,

Welcome to the Auth0 Community!

This post will clear things up:

Unable to authorized with the custom domain

Hi, I successfully setup a custom domain and it was verified. Updated my custom Login Page with the needed settings mentioned in the documentation. But when I tried to do a test cURL with the custom domains, I got {"error":"access_denied","error_description":"Service not enabled within domain: https://devlogin.<domain>.com/api/v2/"} and this is my cURL. curl --request POST \ --url https://devlogin.<domain>.com/oauth/token \ --header 'content-type: application/json' \ --data '{"client_id":"<…

If you are trying to make a request to your API, you need to use the APIs identifier which can be found here:

You are supposed to use your canonical domain instead of your custom domain.

If you have any other questions for us feel free to let us know.

Have a good one,
Vlad