如何在LinkedIn Rest API v2上分享公司页面?

I have created an app and verified it.

I have retrieved the access_token and the linkedin_id.

I have managed to publish posts on linkedin.

After I share I get this message stdClass Object ( [id] => urn:li:share:6555444310316195840 )

The json looks like this:

    $body_json='        
            {
    "author": "urn:li:person:'.$linkedin_id.'",
    "lifecycleState": "PUBLISHED",
    "specificContent": {
        "com.linkedin.ugc.ShareContent": {
            "shareCommentary": {
                "text": "Share some url!"
            },
            "shareMediaCategory": "ARTICLE",
            "media": [
                {
                    "status": "READY",
                    "description": {
                        "text": "NEWS."
                    },
                    "originalUrl": "https://news.test.ce",
                    "title": {
                        "text": "TEST"
                    }
                }
            ]
        }
    },
    "visibility": {
        "com.linkedin.ugc.MemberNetworkVisibility": "CONNECTIONS"
    }
}';

The code is :

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, "https://api.linkedin.com/v2/ugcPosts");
    curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json',
                                                "x-li-format"   => "json",
                                                    'Authorization: Bearer '.$access_token));
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS,$body_json);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    $result = curl_exec($ch);
    $result_decoded = json_decode($result);

I see the post if I go to notifications , but it's not visible on my company's page.

How can I make the post visible in my company page?

I have tried to replace in json_body, the author, with

"author": "urn:li:organization:'.$linkedin_id.'",

and the linkedin_id this case is the company id (previously I used my own linkedin_id)

But I get this error :

stdClass Object ( [serviceErrorCode] => 100 [message] => Field Value validation failed in REQUEST_BODY: Data Processing Exception while processing fields [/author] [status] => 403 ) 

I have all tried to call GET /organizations/org_id but I get this error

 {"serviceErrorCode":100,"message":"Not enough permissions to access: GET /organizations/org_id","status":403}

BUT I am the admin of the company , I can access the admin page ...

How do I share on my own company page?