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":"VpDgXcB7bUvivR7kJjppzQAAAAAAAAABhd6O5Q6lFi1W1aUJioEJVaqST3wz9--rrA-iIjTrryqpLALjFXeFtTaSRNTSw3wJaevoZFO-F8xRpH44UWWk_6QjJIa5uIzfCVw6wY8Vd4Epo_yiZfZWZTeabz-ywE9keOPUvX_pYRJrz5i2qnQxsZj9mjmlzUc_5RIMvRo2Mi9aqla2CJbC8l1ObK9HcfYU_wwD74h10sxgzE_XloUwQZN1klYA_0BdHSDMbA==","error_description":"The request is missing a required parameter : code","error":"invalid_request","request_id":"54dda809-831e-4e35-84bf-2a67bc7ff9be"}"
Array
(
    [error_index] => VpDgXcB7bUvivR7kJjppzQAAAAAAAAABhd6O5Q6lFi1W1aUJioEJVaqST3wz9--rrA-iIjTrryqpLALjFXeFtTaSRNTSw3wJaevoZFO-F8xRpH44UWWk_6QjJIa5uIzfCVw6wY8Vd4Epo_yiZfZWZTeabz-ywE9keOPUvX_pYRJrz5i2qnQxsZj9mjmlzUc_5RIMvRo2Mi9aqla2CJbC8l1ObK9HcfYU_wwD74h10sxgzE_XloUwQZN1klYA_0BdHSDMbA==
    [error_description] => The request is missing a required parameter : code
    [error] => invalid_request
    [request_id] => 54dda809-831e-4e35-84bf-2a67bc7ff9be
)