Persistent 404 Error with Google Ads API v19 Connection

[Sacha Albarda]

Can anyone please help me with diagnosing why the API endpoint is returning a 404 error despite proper configuration?

So far, I've tried:

- Verifying correct project configuration
- Confirmed API is enabled
- Recreated OAuth credentials
-
 Tried testing with simple GAQL query to fetch campaign data

My problem:

- Every API call results in a 404 (Not Found) error
- Tested multiple API versions (v14, v15, v16, v17, v18 and v19)
- API is confirmed as enabled in Google Cloud Console
- OAuth authentication completes successfully
- My developer token is valid (Basic)
- Customer ID is correctly formatted (no hyphens)
- I have a manager account (correctly formatted too)
- I added my script below, with auth. codes redacted.

I am not a coder by profession and I use Claude Sonnet to get me this far. Ironically, the script for Google Analytics performs flawlessly - I thought this would be "easy" too but I hit a brick wall with the script being unable to move beyond the 404./

// Account info

const MANAGER_ID = '000000000'; // Manager Account ID

const CUSTOMER_ID = '000000000'; // Customer ID

const DEVELOPER_TOKEN = '000000000'; // Your developer token

function testGoogleAdsApiConnection() {

// Simple GAQL query to fetch one campaign

const query = `

SELECT

campaign.id,

campaign.name

FROM campaign

LIMIT 1

`;

try {

const url = `https://googleads.googleapis.com/v19/customers/${CUSTOMER_ID}:search`;

const response = UrlFetchApp.fetch(url, {

method: 'post',

headers: {

'developer-token': DEVELOPER_TOKEN,

'login-customer-id': MANAGER_ID,

'Content-Type': 'application/json',

'Authorization': 'Bearer ' + ScriptApp.getOAuthToken()

},

payload: JSON.stringify({

query: query

}),

muteHttpExceptions: true

});

// Log the response

Logger.log('Response Code: ' + response.getResponseCode());

Logger.log('Response Content: ' + response.getContentText());

} catch (e) {

Logger.log('Error: ' + e.toString());

}

}