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":"qJTAniLU7EGopC0B6L_PmwAAAAAAAAABJhxOt7ZTG92a8Ab414oAdxjYwzwFDD8cKwdb1zDSDpVhsKoxsBoOYUOEuAng3s3o77CuvX3igBTxlvacz9IBgtS-8U7LHz7Tmqjilifd-gjkE5FoYmozsrx-TlPzpkAbSQz2Xcz-R_AkOMYnqy6b5xjVtyFgAZFywidgV1BQAXG3T_qPq24drtk_G423thkMpKdgZloMc8CAtp79zwfEgUd2JtwwHW1Prwa0ZQ==","error_description":"The request is missing a required parameter : code","error":"invalid_request","request_id":"5122ba21-70f3-4c6b-913b-ac30075075f9"}"
Array
(
    [error_index] => qJTAniLU7EGopC0B6L_PmwAAAAAAAAABJhxOt7ZTG92a8Ab414oAdxjYwzwFDD8cKwdb1zDSDpVhsKoxsBoOYUOEuAng3s3o77CuvX3igBTxlvacz9IBgtS-8U7LHz7Tmqjilifd-gjkE5FoYmozsrx-TlPzpkAbSQz2Xcz-R_AkOMYnqy6b5xjVtyFgAZFywidgV1BQAXG3T_qPq24drtk_G423thkMpKdgZloMc8CAtp79zwfEgUd2JtwwHW1Prwa0ZQ==
    [error_description] => The request is missing a required parameter : code
    [error] => invalid_request
    [request_id] => 5122ba21-70f3-4c6b-913b-ac30075075f9
)