Creating carousel using LinkedIn APIs

Question

I have been trying to use the LinkedIn APIs to post a carousel. I looked into the documentation but the only mention of Carousel is in Carousel Ads.

Upon some research, I could see that the PDF is being converted to images and then used as the carousel.

Some applications like Taplio, and Supergrow have the feature to post Carousels.

I tried using "/v2/ugcPosts/" API to post images by setting "shareMediaCategory": "CAROUSEL" (based on the documentation here).

But I got the following error:

{
  "message": "com.linkedin.content.common.ResponseException: Carousel post must be a sponsored post: {lifecycleState=PUBLISHED, specificContent={com.linkedin.ugc.ShareContent={shareCommentary={text=Testing}, shareMediaCategory=CAROUSEL, media=[{thumbnails=[], status=READY, media=urn:li:digitalmediaAsset:ASSET_URN}, {thumbnails=[], status=READY, media=urn:li:digitalmediaAsset:ASSET_URN}]}}, visibility={com.linkedin.ugc.MemberNetworkVisibility=PUBLIC}, author=urn:li:member:URN, clientApplication=urn:li:developerApplication:ID, ugcOrigin=API, id=urn:li:share:ID, distribution={feedDistribution=MAIN_FEED}}.",
  "status": 403
}

Here is the payload:

{
  "author": "urn:li:person:USER_URN",
  "lifecycleState": "PUBLISHED",
  "specificContent": {
    "com.linkedin.ugc.ShareContent": {
      "shareCommentary": {
        "text": "Testing"
      },
      "shareMediaCategory": "CAROUSEL",
      "media": [
        {
        "status": "READY",
        "media": "urn:li:digitalmediaAsset:ASSET_URN"
      },
      {
        "status": "READY",
        "media": "urn:li:digitalmediaAsset:ASSET_URN"
      }
        ]
    }
  },
  "visibility": {
    "com.linkedin.ugc.MemberNetworkVisibility": "PUBLIC"
  }
}

Any help would be really appreciated.

Regards.

I was trying to post a carousel on LinkedIn using "Share on LinkedIn" APIs

Update: I am specifically trying to use PDFs to create carousels as LinkedIn UI does using APIs. But there is no documentation to do so.