New Tesla Fleet API Integration Failing with 412 Precondition Failed (App Activation Issue?)

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Hello everyone,

I’m hoping someone can shed some light on an issue I’m facing while setting up the official Tesla integration on a new Home Assistant installation. My goal is to create automations for my vehicle, but I’m completely stuck at the authentication step.

Here is what I have done:

  1. I created a new application in the Tesla Developer Portal (developer.tesla.com).
  2. I received my Client ID and Client Secret.
  3. I have correctly configured the Redirect URI in the Tesla Portal to be exactly: https://my.home-assistant.io/redirect/oauth

Here is what happens:

  1. In Home Assistant, I go to Settings > Add Integration and select Tesla.
  2. I enter my Client ID and Client Secret.
  3. Home Assistant correctly redirects me to the auth.tesla.com login page.
  4. I can successfully log in with my Tesla credentials (email, password, and 2FA).
  5. I see the consent screen asking me to grant permissions to my application, and I click “Allow”.

The Problem:

Immediately after clicking “Allow”, instead of being redirected back to Home Assistant to complete the setup, my browser shows an “Access Denied” page from Tesla’s servers.

Through extensive local testing with Python scripts, I can confirm that the API is returning a 412 Client Error: Precondition Failed for any request to a fleet-api endpoint (like GET /api/1/vehicles). This happens even when using a freshly generated access token from the official OAuth flow.

My Conclusion / Question for the Community:

Since the OAuth login itself works but all subsequent API calls are blocked with a 412 error, my conclusion is that this is not a configuration error on my side, but an issue with my developer application itself. It seems my new app has not been fully activated or provisioned on Tesla’s backend.

  1. Has anyone else who recently created a new Tesla developer application experienced this same 412 Precondition Failed block?
  2. Is there a known waiting period for new applications to be fully activated by Tesla?
  3. Is there a currently working contact method for Tesla’s developer support to request an application be reviewed or activated? (The known fleetapi@ email seems to be inactive).

Any insights or shared experiences would be greatly appreciated. It feels like I’m at the final step but am blocked by a server-side permission issue.

Thank you!