The OAuth client was deleted error

[official bazutte]

Dear Google Support Team,

I accidentally deleted my Google Cloud project—and with it, the associated OAuth 2.0 Client—used for user authentication in my application. I promptly restored the project within the 30-day recovery window, and the credentials now appear normal in the Google Cloud Console.

However, more than 18 hours after restoration, users (including myself) still cannot sign in with Google. The following message continues to appear:

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Access blocked: Authorization Error

The OAuth client was deleted.
If you are a developer of this app, see error details.
Error 401: deleted_client



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Could you please advise how to resolve this issue and fully restore sign-in functionality?

[Google Ads API Forum Advisor]

Hi,

Thank you for contacting the Google Ads API support team. 

Please note that your concern is out of scope for our team as our team only provides support for Google Ads API related concerns and technical implementations. I would recommend you to contact the GCP Product Support team for further assistance regarding your concern as they are better equipped to address your concerns.

Thanks,
 

Google Ads API Team

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[2025-07-08 14:24:50Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01rhPzc:ref" (ADR-00317915)