How to solve oAuth issue using Linkedin API?

Question

PHP

Hello. I decided to get data about the company from the Linkedin API. As a result, I got up on Access Token . Using the steps: https://developer.linkedin.com/docs/oauth2 stuck at 3.
My task now is to get a token, which I can't get for reasons I don't understand.
What I have:
1)
I got client_id and client_secret respectively. I set up the url on the linkedin side to http://demo.test/backend/linkedin.
2)
Collected the URL for authorization

https://www.linkedin.com/oauth/v2/authorization?response_type=code&client_id=725gqxsyeaz0dr&state=b0316f2ddd3a0af2b44efcff3f60836c&redirect_uri=http%3A%2F%2Fdemo.test%2Fbackend%2Flinkedin

3)
On my callback I get:

grant_type=authorization_code&code=AQQ8POkuOe4TKjLrVaa34bz0HpMEk18Fohvqy9Dv9G6RoApogpDai_AN30QcD6_WTCNwxi4OjvMnZSDOzWjeotoNzFdMdK3hHvekCThothp6KoKq3F3h4dR37AaNOw3UduZ_DUfBwf-cQzt33ht32StJccNo_trFRtKfI-nw&redirect_uri=http%3A%2F%2Fdemo.test%2Fbackend%2Flinkedin&client_id=725gqxsyeaz0dr&client_secret=pxtGcphOs8feMXS0

And here I already have doubts, in the dock they clearly have the code listed as
code = 987654321

grant_type=authorization_code&code=987654321&redirect_uri=https%3A%2F%2Fwww.myapp.com%2Fauth%2Flinkedin&client_id=123456789&client_secret=shhdonottell

And mine turns out:

AQQ8POkuOe4TKjLrVaa34bz0HpMEk18Fohvqy9Dv9G6RoApogpDai_AN30QcD6_WTCNwxi4OjvMnZSDOzWjeotoNzFdMdK3hHvekCThothp6KoKq3F3h4dR37AaNOw3UduZ_DUfBwf-cQzt33ht32StJccNo_trFRtKfI-nw

In the toga I make a request to get a token:

if (LinkedIn::isAuthenticated()) {
            $url = parse_url("http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]");
            parse_str($url['query'], $url);

            $code = $url['code'];

            $data = [
                "grant_type" => "authorization_code",
                "code" => $code,
                "redirect_uri" => "http://demo.test/backend/linkedin",
                "client_id" => "725gqxsyeaz0dr",
                "client_secret" => "pxtGcphOs8feMXS0"
            ];

            $url2 = "https://www.linkedin.com/oauth/v2/accessToken";

            $curl = curl_init();
            curl_setopt($curl, CURLOPT_HTTPHEADER, ['Content-Type: application/x-www-form-urlencoded']);
            curl_setopt($curl, CURLOPT_POST, 1);
            curl_setopt($curl, CURLOPT_POSTFIELDS, http_build_query($data));
            curl_setopt($curl, CURLOPT_URL, $url2);
            curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
            
            $result = curl_exec($curl);
            curl_close($curl);

            $result_array = json_decode($result, true);

            dump(http_build_query($data));
            dump($result_array);

            //we know that the user is authenticated now. Start query the API
            //dd(LinkedIn::get('/v1/companies/11812834/updates?format=json'));
        }elseif (LinkedIn::hasError()) {
            echo  "User canceled the login.";
            exit();
        }

        //if not authenticated
        $url = LinkedIn::getLoginUrl();
        dump($url);

        echo "<a href='$url'>Login with LinkedIn</a>";
        exit();
    }

And I get a response:

array:2 [▼
  "error" => "invalid_request"
  "error_description" => "Unable to retrieve access token: appid/redirect uri/code verifier does not match authorization code. Or authorization code expired. Or external member binding e ▶"
]

What am I doing wrong?
PS Kay and Sikrit are fake.

Answer 1

well, it’s obvious that the test code is in the documentation,
look at what you have generated and compare with the one generated manually according to the documentation