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":"xQZGrC_5Sd-z2m6F22m91wAAAAAAAAABZsivYN1_cHEqziiBc6-4bplNQLx4SzyliiKNK8K0oRAPX556pOtDB8BUq4WhIuX-of85XEwZcwW0AsQZ2boEAbFEGVB6laOlVHgX8UYmld0TkE3uT-45MF8uFP2h8F2SQWTp1tq8Lnv-Hy_6Vaezmlb8FJSudK9YA-oNvqIOmZwl7csRUWXJKH2_xlvN01J787I0W5fh0S7dAeoHMqj-eDJBmzuCmJfPD2xZBg==","error_description":"The request is missing a required parameter : code","error":"invalid_request","request_id":"d04c4d35-21c3-4dd0-b7b3-c526beae7146"}"
Array
(
    [error_index] => xQZGrC_5Sd-z2m6F22m91wAAAAAAAAABZsivYN1_cHEqziiBc6-4bplNQLx4SzyliiKNK8K0oRAPX556pOtDB8BUq4WhIuX-of85XEwZcwW0AsQZ2boEAbFEGVB6laOlVHgX8UYmld0TkE3uT-45MF8uFP2h8F2SQWTp1tq8Lnv-Hy_6Vaezmlb8FJSudK9YA-oNvqIOmZwl7csRUWXJKH2_xlvN01J787I0W5fh0S7dAeoHMqj-eDJBmzuCmJfPD2xZBg==
    [error_description] => The request is missing a required parameter : code
    [error] => invalid_request
    [request_id] => d04c4d35-21c3-4dd0-b7b3-c526beae7146
)