Persistent 404 Not Found Error with Google Ads API via HTTP Request Node

Questions
1

Hello, I'm encountering a persistent "404 Not Found" error when trying to make a POST request to the Google Ads API search endpoint. I've already gone through an extensive debugging process and have ruled out all common causes.

Endpoint: POST https://googleads.googleapis.com/v16/customers/{customer-id}/googleAds:search

Error Message: 404. That’s an error. The requested URL /v16/customers/{customer-id}/googleAds:search was not found on this server. That’s all we know.

Here's what I've already verified and tried:

  • Workflow: I am using a standard HTTP Request node.

  • Permissions: I have confirmed via the Google Ads UI that my Manager Account (MCC) has Admin and Owner access to the client account I'm querying.

  • Customer ID: The Customer ID in the URL is correct and does not contain dashes.

  • Google Cloud Project:

    • The OAuth Consent Screen app has been published and is "In Production".

    • The "Google Ads API" is explicitly enabled in the project's API library.

  • Credentials:

    • I have completely deleted and recreated the OAuth 2.0 Client ID in GCP.

    • I have completely deleted and recreated the credential in n8n using the new keys and have successfully re-authenticated.

  • n8n Node:

    • I have deleted the failing HTTP Request node and created a new one from scratch, manually inputting all parameters.

    • The node correctly includes the "login-customer-id" header.

    • I have also explicitly added the "developer-token" to the headers, and the error still persists.

  • API Version: I confirmed that using API v16 is correct. Changing to other versions like v19 or v20 results in a "400 Bad Request" error, indicating v16 is the valid endpoint.

Despite all these steps, the 404 error remains. This suggests the issue might be environmental (networking) or a bug in my n8n instance.

Could you please guide me on how to obtain and share the necessary detailed logs to diagnose this further?

2

Hey can you try getting the raw request from the HTTP node?

  • Open your failing HTTP Request node.
  • Scroll down and enable “Full Response”.
  • Run the node.
  • The execution data will then include both the response object (status, headers, body) and the raw request sent.
  • You can copy-paste that JSON block (masking tokens) to share for debugging.

Also, can you let me know if you managed to do a request with the same customer-id and payload to Google successfully via any other method?

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