In facebook marketing api leadgen_context_cards edge is not accepting cover_photo

Question

I am following https://developers.facebook.com/docs/marketing-api/guides/lead-ads/create/v2.8 to create context card for lead ad. document says it will accept cover_photo field. But if we try to create context from Graph API Explorer with following params

https://developers.facebook.com/tools/explorer/xxxxxx?method=POST&path=<PAGE_ID>%2Fleadgen_context_cards&version=v2.8&title=sample-title-1&style=PARAGRAPH_STYLE&content=[%22sample%20content%201%22]&button_text=Get%20Started&cover_photo=http://xxxxx.s3.amazonaws.com/sample/sampleimage.png

its showing following

{
  "error": {
    "message": "An unknown error has occurred.",
    "type": "OAuthException",
    "code": 1,
    "fbtrace_id": "xxxxxx"
  }
}

And if we click on fgtrace_id it showing following

{
  "error": {
    "message": "(#803) Some of the aliases you requested do not exist: xxxxx",
    "type": "OAuthException",
    "code": 803,
    "fbtrace_id": "yyyyyy"
  }
}

If we remove cover_photo param we are able to create context cards.

Thanks.

Update 1

I have tried to upload the actual image file. Still facing same issue. Following is code and response.

        HttpClient httpClient = HttpClientBuilder.create().build();
        HttpPost httppost = new HttpPost(GRAPH_FACEBOOK_LEADGEN_CONTEXT_CARDS);

        File file = new File(IMAGE_PATH);
        ContentBody cbFile = new FileBody(file, ContentType.create(MimeTypeUtils.IMAGE_PNG_VALUE));

        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.addTextBody("access_token", ACCESS_TOKEN);
        builder.addTextBody("title", "sample-title-1");
        builder.addTextBody("style", "PARAGRAPH_STYLE");
        builder.addTextBody("content", "['sample-title-1']");
        builder.addTextBody("button_text", "Get Started");
    // builder.addPart("cover_photo", cbFile);
    // builder.addBinaryBody("cover_photo", file);
    // builder.addBinaryBody("cover_photo", file, ContentType.create(MimeTypeUtils.IMAGE_PNG_VALUE),IMAGE_PATH);
    // builder.addBinaryBody("cover_photo", new FileInputStream(file));

    httppost.setEntity(builder.build());
    System.out.println("executing request " + httppost.getRequestLine());
    HttpResponse response = httpClient.execute(httppost);
    HttpEntity resEntity = response.getEntity();

    System.out.println(response.getStatusLine());
    if (resEntity != null) {
        System.out.println(EntityUtils.toString(resEntity));
    }

Response:

executing request POST https://graph.facebook.com/167067040143315/leadgen_context_cards HTTP/1.1
HTTP/1.1 500 Internal Server Error
{"error":{"message":"An unknown error has occurred.","type":"OAuthException","code":1,"fbtrace_id":"CHG1SYDq9zn"}}

Update 2

With following code I am able to create context card. but cover photo is missing.

URIBuilder uriBuilder = new URIBuilder(
                GRAPH_FACEBOOK_LEADGEN_CONTEXT_CARDS);
        uriBuilder.setParameter("access_token", ACCESS_TOKEN);
        uriBuilder.setParameter("title", "sample-title-1");
        uriBuilder.setParameter("style", "PARAGRAPH_STYLE");
        uriBuilder.setParameter("content", "['sample-title-1']");
        uriBuilder.setParameter("button_text", "Get Started");
        HttpClient httpClient = HttpClientBuilder.create().build();
        HttpPost httppost = new HttpPost(uriBuilder.build());

        File file = new File(IMAGE_PATH);
        ContentBody cbFile = new FileBody(file,
                ContentType.create(MimeTypeUtils.IMAGE_PNG_VALUE));
        byte[] bytes = FileUtils.readFileToByteArray(file);

        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
         builder.addPart("cover_photo", cbFile);
        // builder.addBinaryBody("cover_photo", file);
        // builder.addBinaryBody("cover_photo", file,
        // ContentType.create(MimeTypeUtils.IMAGE_PNG_VALUE),IMAGE_PATH);
        // builder.addBinaryBody("cover_photo", new FileInputStream(file));
        // builder.addBinaryBody("cover_photo", bytes,
        // ContentType.create(MimeTypeUtils.IMAGE_PNG_VALUE),IMAGE_PATH);

        httppost.setEntity(builder.build());
        httppost.addHeader(new BasicHeader("Content-Type",
                ContentType.MULTIPART_FORM_DATA.getMimeType()));
        System.out.println("executing request " + httppost.getRequestLine());
        HttpResponse response = httpClient.execute(httppost);
        HttpEntity resEntity = response.getEntity();

        System.out.println(response.getStatusLine());
        if (resEntity != null) {
            System.out.println(EntityUtils.toString(resEntity));
        }

Answer 1

As per my observation in https://business.facebook.com's UI. Its first uploading image and passing id in cover_photo_id.

Uploaded unpublished photo to page/photos and passed generated Id in context_card's cover_photo_id. and its worked.