# Callback url throwing error

**URL:** <https://community.auth0.com/t/callback-url-throwing-error/194708>\
**Category:** Get Help\
**Tags:** signup-prompt-new-experience, login-experience\
**Created:** [November 20, 2025, 10:11am UTC](https://community.auth0.com/t/callback-url-throwing-error/194708 "2025-11-20T10:11:51Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![manors](https://sea1.discourse-cdn.com/auth0/user_avatar/community.auth0.com/manors/32/71118_2.png) [@manors](https://community.auth0.com/u/manors)\
**Post date:** [November 20, 2025, 10:11am UTC](https://community.auth0.com/t/callback-url-throwing-error/194708/1 "2025-11-20T10:11:51Z")

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i am trying to use nextjs sdk and have configured an regular web app in auth0 using local host, but after login getting the below mentioned error - “The client\_secret or client\_assertion field is required, or it should be mTLS request” let me know if i am missing something on this .

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**Author:** ![vlad.murarasu](https://sea1.discourse-cdn.com/auth0/user_avatar/community.auth0.com/vlad.murarasu/32/72793_2.png) [@vlad.murarasu](https://community.auth0.com/u/vlad.murarasu)\
**Post date:** [November 20, 2025, 1:27pm UTC](https://community.auth0.com/t/callback-url-throwing-error/194708/3 "2025-11-20T13:27:16Z")

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Hi @manors,

The error indicates that your Next.js application, acting as a confidential client, is failing to provide the required **Client Secret** to Auth0 when exchanging the authorization code for tokens. This is caused by a missing or incorrectly loaded environment variable. Ensure the `AUTH0_CLIENT_SECRET` is correctly configured in your Next.js environment.

If you have any further questions, please don’t hesitate to reach out.

Have a good one,  
Vlad

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<div class="post-metadata">

**Author:** ![manors](https://sea1.discourse-cdn.com/auth0/user_avatar/community.auth0.com/manors/32/71118_2.png) [@manors](https://community.auth0.com/u/manors)\
**Post date:** [November 20, 2025, 3:34pm UTC](https://community.auth0.com/t/callback-url-throwing-error/194708/4 "2025-11-20T15:34:35Z")

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hi murarasu,

Thanks for your reply, i have followed the link from auth0 quick starts guide to install next.js sdk and i have configured regular web application in auth0 tenant and utilised the same client id and secret in the sdk configuration as well,

not sure what i am missing could you please help on this.

AUTH0\_DOMAIN=

AUTH0\_CLIENT\_ID=

AUTH0\_CLIENT\_SECRET=

AUTH0\_SECRET=Om1PHDQq2MSGYWp7rBluFzhs5tVvNnf8Tyi40gIbw96jxJUEcCLeoARXKZa3kd

APP\_BASE\_URL=

we have configured all this values from .env.local file

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<div class="post-metadata">

**Author:** ![vlad.murarasu](https://sea1.discourse-cdn.com/auth0/user_avatar/community.auth0.com/vlad.murarasu/32/72793_2.png) [@vlad.murarasu](https://community.auth0.com/u/vlad.murarasu)\
**Post date:** [November 20, 2025, 4:17pm UTC](https://community.auth0.com/t/callback-url-throwing-error/194708/5 "2025-11-20T16:17:00Z")

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Hi @manors,

You have to input all your variables into the `.env.local` file, not just the `AUTH0_SECRET`.

[https://auth0.com/docs/quickstart/webapp/nextjs#dashboard](https://auth0.com/docs/quickstart/webapp/nextjs#dashboard)

You need to provide your application’s domain, client ID, and client secret for the application to function correctly.

Have a good one,  
Vlad

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**Author:** ![system](https://global.discourse-cdn.com/auth0/original/3X/b/5/b560f266932fcce5d57f09a6595bd50518cae3f3.jpeg) [@system](https://community.auth0.com/u/system)\
**Post date:** [December 4, 2025, 4:17pm UTC](https://community.auth0.com/t/callback-url-throwing-error/194708/6 "2025-12-04T16:17:50Z")

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