Success Login and a Failed Exchange

I configured an API and application.
I have an angular app. I can login wit my user.
I see that in the logs (success login).
But than I have a Failed Exchange.
In the chrome dev tools, I see the following:

POST 401

hi @filip.debacker and thanks for reaching out to Auth0 Support!

Sounds like that error is related to your Authorization code flow not working as expected, here’s a list of our event type codes which may be useful.

You mentioned having an Angular application, is it modeled in Auth0 as a SPA or Regular Web Application (RWA)? For front end applications like that we recommend it being a SPA, in which case the Auth Code Flow is not recommended and should use the Implicit Flow, more on that here:

Please review those materials and if you’re still facing issues, could you please send me your tenant in a DM and I can review your setup further.

Best Regards,

Thanks for the info.
I’ve implemented the authorization like described in the Login and API sample. So that is the Implicit Flow.

I created a new Application, now I can login.
But when I check my token with, I get a signature error due to padding.

Also, localhost works fine, no error in dev console.

On the prod server, I got an error:

ERROR NullInjectorError: StaticInjectorError[t -> t]:
StaticInjectorError(Platform: core)[t -> t]:
NullInjectorError: No provider for t!
at t.get (

@colin.coutts I am getting the same error with my Angular SPA. I followed the tutorial and I am also getting the FAILED EXCHANGE ERROR for both Google/Facebook Social Logins

  "date": "2020-08-13T08:12:55.226Z",
  "type": "feacft",
  "description": "Unauthorized",
  "connection_id": "",
  "client_id": "gNkJFP7YEvD4OrBdbgjHYZzM8XwkhjYS",
  "client_name": null,
  "ip": "",
  "user_agent": "Safari 13.1.0 / Mac OS X 10.15.4",
  "details": {
    "code": "*************4s5"
  "hostname": "",
  "user_id": "",
  "user_name": "",
  "log_id": "90020200813081256620000465921382865527023048504050188338",
  "_id": "90020200813081256620000465921382865527023048504050188338",
  "isMobile": false

I am getting this error even after successful SignUp for Angular SPA

I found the same issue with my react app today.
You can try this.

First, I created a new app setting.
Then I exported my settings, and compare it.
I found differences between old app and new app.
that differences are grant_types and token_endpoint_auth_method.

Hi @masaki @sagun786 and @filip.debacker!

Thanks for reaching out! Let’s see what we can do :slightly_smiling_face:

Would you mind all sending me your tenant name in a DM as well as a .har file for me to look into this further? More details on that here:

Just so I have some clarity on this, are you seeing these errors on all logins or are they specific only to Social Logins (Facebook/Google etc.)? Also is this issue only when you deploy your app or is it reproducible locally as well?

@masaki what were the differences that you noticed? The token_endpoint_auth_method should be set to none for a SPA, this would be worth confirming as that could cause an Unauthorized error.

Best Regards,

I have shared the details on an email(DM) with you @colin.coutts. I am still not sure what’s not working inspite of a well laid out tutorial. @masaki did you find any luck resolving this bug (please can you share some links if you have managed to resolve this)

@sagun786 @colin.coutts
Our issue has been solved by the following changes.


  - authorization_code
  - implicit
  - refresh_token
  - client_credentials
token_endpoint_auth_method: client_secret_post


  - authorization_code
  - implicit
  - refresh_token
token_endpoint_auth_method: none

Perfect you have eventually figured it out and thanks for sharing with the rest of community!

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