# Openidconnect.net: Failed to retrieve token

**URL:** <https://community.auth0.com/t/openidconnect-net-failed-to-retrieve-token/197658>\
**Category:** Get Help\
**Tags:** other, test\
**Created:** [February 25, 2026, 7:56pm UTC](https://community.auth0.com/t/openidconnect-net-failed-to-retrieve-token/197658 "2026-02-25T19:56:18Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![nhalstead](https://sea1.discourse-cdn.com/auth0/user_avatar/community.auth0.com/nhalstead/32/78557_2.png) [@nhalstead](https://community.auth0.com/u/nhalstead)\
**Post date:** [February 25, 2026, 7:56pm UTC](https://community.auth0.com/t/openidconnect-net-failed-to-retrieve-token/197658/1 "2026-02-25T19:56:18Z")

</div>

I’m testing an OIDC implementation from my machine and using ngrok to expose it for backchannel requests.

I’m able to go through the first half of the auth, but when I get to `Exchange Code from Token` the request always fails with a 500 response for `code_to_token`.

```auto
{
    "error": "Failed to retrieve token"
}

```

No requests are being made to the backchannel URLs. Are ngrok domains blocked from backchannel requests, or am I missing something? I’ve tried other tools for OIDC testing, and they work just fine.

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**Author:** ![nik.baleca](https://sea1.discourse-cdn.com/auth0/user_avatar/community.auth0.com/nik.baleca/32/68749_2.png) [@nik.baleca](https://community.auth0.com/u/nik.baleca)\
**Post date:** [February 27, 2026, 5:02pm UTC](https://community.auth0.com/t/openidconnect-net-failed-to-retrieve-token/197658/3 "2026-02-27T17:02:05Z")

</div>

Hi @nhalstead

Welcome to the Auth0 Community!

What type of application are you using? Regular or SPA?

If you are using a Regular app, I understand that you have configured your authentication profile to be `Private Key JWT`? If so, does setting it to `Client Secret (Post)` solve the issue? You will need to send the client secret and id value in the request body.

Looking forward to your reply!

Kind Regards,  
Nik

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<div class="post-metadata">

**Author:** ![nik.baleca](https://sea1.discourse-cdn.com/auth0/user_avatar/community.auth0.com/nik.baleca/32/68749_2.png) [@nik.baleca](https://community.auth0.com/u/nik.baleca)\
**Post date:** [March 12, 2026, 4:17pm UTC](https://community.auth0.com/t/openidconnect-net-failed-to-retrieve-token/197658/4 "2026-03-12T16:17:03Z")

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Hi again @nhalstead

Since you have not replied back regarding the matter, I will be marking my previous post as the Solution.

Feel free to jump in or post again in case this topic is closed referencing this post!

Kind Regards,  
Nik

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<div class="post-metadata">

**Author:** ![system](https://global.discourse-cdn.com/auth0/original/3X/b/5/b560f266932fcce5d57f09a6595bd50518cae3f3.jpeg) [@system](https://community.auth0.com/u/system)\
**Post date:** [March 26, 2026, 4:17pm UTC](https://community.auth0.com/t/openidconnect-net-failed-to-retrieve-token/197658/5 "2026-03-26T16:17:54Z")

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