You cannot use application_fee with this payment. | MercadoPago MarketPlace Laravel

[emasans2000]

Hi,
I'm currently integrating MercadoPago into my Laravel application, and I'm encountering an issue when trying to process a payment. The error message I receive:
"You cannot use application_fee with this payment."

The documentation says "This error occurs because the Access Token being used was not obtained via OAuth. Make sure to use an Access Token generated through OAuth." but I've obtained the AToken via oauth.

Route /connect-mercadopago

 $codeVerifier = bin2hex(random_bytes(32));
    session(['mp_code_verifier' => $codeVerifier]);

    // Generate code challenge
    $codeChallenge = rtrim(strtr(base64_encode(hash('sha256', $codeVerifier, true)), '+/', '-_'), '=');

    // auth params
    $queryParams = http_build_query([
        'response_type' => 'code',
        'client_id' => env('MERCADOPAGO_CLIENT_ID'),
        'redirect_uri' => url('/callback-mercadopago'),
        'code_challenge' => $codeChallenge,
        'code_challenge_method' => 'S256',
    ]);

    
    return redirect(env('MERCADOPAGO_GETAUTH') . $queryParams);

MERCADOPAGO_GETAUTH=https://auth.mercadopago.com/authorization?

/**
     * @throws ConnectionException
     */
    public function callBackToken(Request $request)
    {
        $code = $request->input('code');
        $codeVerifier = session('mp_code_verifier');

        if (!$code || !$codeVerifier) {
            return response()->json(['error' => 'Missing parameters.'], 400);
        }

        $postData = [
            'client_id'     => env('MERCADOPAGO_CLIENT_ID'),
            'client_secret' => env('MERCADOPAGO_CLIENT_SECRET'),
            'grant_type'    => 'authorization_code',
            'code'          => $code,
            'redirect_uri'  => env('REDIRECT_URL'),
            'code_verifier' => $codeVerifier,
        ];

        $response = Http::asForm()->post(env('MERCADOPAGO_OAUTH'), $postData);

        if ($response->failed() || $response->status() >= 400) {
            return response()->json(['error' => $response->body()], $response->status());
        }

        $responseData = $response->json();

        if (
            !is_array($responseData) ||
            !isset($responseData['access_token'], $responseData['refresh_token'], $responseData['expires_in'])
        ) {
            return response()->json(['error' => 'Invalid token response.'], 500);
        }

        $tokenData = $this->encryptTokenData($responseData);

        if (!$this->saveMercadoPagoToken($request, $tokenData)) {
            return response()->json(['error' => 'Failed to save token data.'], 500);
        }

        $request->session()->forget('mp_code_verifier');

        return response()->json($responseData, 200);
    }

    /**
     * Encrypt token
     *
     * @param  array  $responseData
     * @return array
     */
    protected function encryptTokenData(array $responseData): array
    {
        return [
            'encrypted_access_token'  => encrypt($responseData['access_token']),
            'encrypted_refresh_token' => encrypt($responseData['refresh_token']),
            'expires_at'              => now()->addSeconds($responseData['expires_in']),
            'public_key'              => encrypt($responseData['public_key'] ?? ''),
        ];
    }

    /**
     * Save encrypted tokens
     *
     * @param  Request  $request
     * @param  array    $tokenData
     * @return bool
     */
    protected function saveMercadoPagoToken(Request $request, array $tokenData): bool
    {
        try {
            $data = array_merge([
                'user_id' => auth()->id(),
            ], $tokenData);

            $request->user()->Seller()->create($data);
            return true;
        } catch (\Exception $e) {
            \Log::error('Error saving MercadoPago token', ['error' => $e->getMessage()]);
            return false;
        }
    }

MERCADOPAGO_OAUTH=https://api.mercadopago.com/oauth/token