[BUG] Amazon Advertising 400 Error

**Describe the bug**
I am using Pipedream's native Amazon Advertising integration with my own approved Amazon Ads API Login with Amazon client.

Amazon Ads API access is approved and the client has the scopes:
advertising::campaign_management
advertising::test:create_account

Pipedream provides this redirect URI:
https://api.pipedream.com/connect/oauth/oFa_gBBiN2o/callback

This exact URL is saved under the Login with Amazon Security Profile → Web Settings → Allowed Return URLs.

However, connecting the Amazon Advertising account from Pipedream still returns:
400 Bad Request
The redirect URI you provided has not been whitelisted for your application
lwa-invalid-parameter-bad-redirect-uri-vendor

The Client ID is recognized correctly and the previous “unknown scope” error disappeared after Amazon approved the Ads API application.

The Amazon Advertising account is an EU / Italy advertiser. Please check whether my native Amazon Advertising connection requires an exception or configuration on the Pipedream side.

**Expected behavior**
Account connected successfully.