Transition to OAuth: HTML to PDF error

Hi everyone,

I am able to convert a URL to PDF using the rest API with JWT credentials, but the same operation doesn’t succeed when switching to OAuth credentials. In the latter case, the PDF output (attached) only contains an error message followed by an error code. 

In both approaches, the same http request is sent. Here is the (python) code for the OAuth approach:

        # Load credentials
        PDF_SERVICES_CLIENT_ID = os.getenv('PDF_SERVICES_CLIENT_ID')
        PDF_SERVICES_CLIENT_SECRET = os.getenv('PDF_SERVICES_CLIENT_SECRET')
        # Obtain access token
        url_access_token = "https://ims-na1.adobelogin.com/ims/token/v3"
        headers = {'Content-Type': 'application/x-www-form-urlencoded'}
        payload = f'grant_type=client_credentials&client_id={PDF_SERVICES_CLIENT_ID}&client_secret={PDF_SERVICES_CLIENT_SECRET}&scope=AdobeID,openid,read_organizations,additional_info.projectedProductContext,additional_info.roles,adobeio_api,read_client_secret,manage_client_secrets,DCAPI'
        response = requests.post(url_access_token, headers=headers, data=payload)
        access_token = response.json().get('access_token')
        # Endpoint for the HTML to PDF conversion service
        api_url = 'https://pdf-services-ue1.adobe.io/operation/htmltopdf'
        # Headers for the request
        headers = {
            'Authorization': f'Bearer {access_token}',
            'Content-Type': 'application/json',
            'x-api-key': os.getenv('PDF_SERVICES_CLIENT_ID'),
        }
        # Data payload for the request
        data = {
            "inputUrl": url,
            "includeHeaderFooter": True,
            "json": "{}",
            "pageLayout": {
                "pageWidth": 11,
                "pageHeight": 8.5
            }
        }
        # POST request to convert HTML to PDF
        response = requests.post(api_url, headers=headers, json=data)

Any clue on what is happening/missing here?

Thanks!