Exception when calling AuthorizationV1Api->getAuthorizationCode: Client error: `POST https://api.amazon.com/auth/o2/token` resulted in a `401 Unauthorized` response:
{"error_description":"Client authentication failed","error":"invalid_client"}

<br />
<b>Warning</b>:  Undefined variable $authorizationCode in <b>/home/amzgreatvaluesto/public_html/amz_sp/sp_api_auth_code.php</b> on line <b>33</b><br />
string(433) "{"error_index":"gLYRH5dvZPUgF4r3MtHjEQAAAAAAAAABL3Ecg7HYFXwKUnbBZ7U1RsyRWmOeF8izvYYjLmblxzs-Megyq8aDy6jy0qhEdrSxYYsfvS7Dc0DB_kb8hDuY_vEFmg2gznlDfX4fBxzyFz3bAmTmGzDlkfqXlOg8vJdCqFA0PTqlFqNMf25EH1U4Jh0mamSzQyHGNMRcOnc96Po_j6krkg_vB7A3DzbVPU4SemierRPyyZgGgcHPuj8fZI7vp7NQpovWboXsbA==","error_description":"The request is missing a required parameter : code","error":"invalid_request","request_id":"9fca1f78-d47e-4e2f-a06b-296246b9ee49"}"
Array
(
    [error_index] => gLYRH5dvZPUgF4r3MtHjEQAAAAAAAAABL3Ecg7HYFXwKUnbBZ7U1RsyRWmOeF8izvYYjLmblxzs-Megyq8aDy6jy0qhEdrSxYYsfvS7Dc0DB_kb8hDuY_vEFmg2gznlDfX4fBxzyFz3bAmTmGzDlkfqXlOg8vJdCqFA0PTqlFqNMf25EH1U4Jh0mamSzQyHGNMRcOnc96Po_j6krkg_vB7A3DzbVPU4SemierRPyyZgGgcHPuj8fZI7vp7NQpovWboXsbA==
    [error_description] => The request is missing a required parameter : code
    [error] => invalid_request
    [request_id] => 9fca1f78-d47e-4e2f-a06b-296246b9ee49
)