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":"GHZTtyBWSSQpy4UrQwf2YAAAAAAAAAABA69S6-rrVs8jx_b6CtFeh8bGbtMy_kHU4unaudBjcABfR9Pj6awfs1GWmHNeaXhry6TdxaOznDlkB45KjtiuiiSeajCGqWNWdAid7CBijjAH1V35Air-xMBmXtrf6FepVbeyQTybokbxvsOPUivXSwhKvAI8IFMTQGTomyHbNFadYVbszCAfegQ7zch8zIYHNtqULJt7j4aF_y9CoGVZLIhfNEnCinfguRPUig==","error_description":"The request is missing a required parameter : code","error":"invalid_request","request_id":"de07a227-0a57-446a-b790-243ff8e86b53"}"
Array
(
    [error_index] => GHZTtyBWSSQpy4UrQwf2YAAAAAAAAAABA69S6-rrVs8jx_b6CtFeh8bGbtMy_kHU4unaudBjcABfR9Pj6awfs1GWmHNeaXhry6TdxaOznDlkB45KjtiuiiSeajCGqWNWdAid7CBijjAH1V35Air-xMBmXtrf6FepVbeyQTybokbxvsOPUivXSwhKvAI8IFMTQGTomyHbNFadYVbszCAfegQ7zch8zIYHNtqULJt7j4aF_y9CoGVZLIhfNEnCinfguRPUig==
    [error_description] => The request is missing a required parameter : code
    [error] => invalid_request
    [request_id] => de07a227-0a57-446a-b790-243ff8e86b53
)