Video share not showing on LinkedIn

I using the LinkedIn API to share a video to a company page. I am using this endpoint : https://api.linkedin.com/v2/ugcPosts

I POST this payload:

{
    "author": "urn:li:company:**company_page_id**",
    "lifecycleState": "PUBLISHED",
    "specificContent": {
        "com.linkedin.ugc.ShareContent": {
            "media": [
                {
                    "media": "urn:li:digitalmediaAsset:**my_asset_id_that_is_ready**",
                    "status": "READY",
                    "title": {
                        "text": "A video!"
                    },
                    "description": {
                        "text": "New vid"
                    }
                }
            ],
            "shareCommentary": {
                "text": "A new video!"
            },
            "shareMediaCategory": "VIDEO"
        }
    },
    "visibility": {
        "com.linkedin.ugc.MemberNetworkVisibility": "PUBLIC"
    }
}

I am getting this back:

{
    "id": "urn:li:ugcPost:**a_post_id**"
}

However the post is never showing up on the page.

If I use a direct link like this:

https://www.linkedin.com/feed/update/urn:li:ugcPost:**a_post_id**/

Then I get this message: Something went wrong. We’re having issues loading the page.

Can anyone help me see what is wrong with this payload?