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":"I_W9NSsO0fE3msnJBBhrYAAAAAAAAAABptAHDrEz6a0guSX_ronHEo1rM1ustPOOZALgPqDdP2w52N-HsIg9C2Y-Z5fzKz2sS6nBXM4VaJp9zU1CphL8Ejq8S8YSBrEKHILPb6WlvlvE831GbmV88u9D_mKW8rGCwqYXEd-EmZy6KuHS74J4rMrRuiXk2mF09dVPUb0Ik4UqXp8dyY3DVpUca5rRMe1CTvBW2JKyqTgrmqUWygnRLeTny9oEHqU69JO4Uw==","error_description":"The request is missing a required parameter : code","error":"invalid_request","request_id":"ea1c4217-5d77-4187-9aff-aec8f357d938"}"
Array
(
    [error_index] => I_W9NSsO0fE3msnJBBhrYAAAAAAAAAABptAHDrEz6a0guSX_ronHEo1rM1ustPOOZALgPqDdP2w52N-HsIg9C2Y-Z5fzKz2sS6nBXM4VaJp9zU1CphL8Ejq8S8YSBrEKHILPb6WlvlvE831GbmV88u9D_mKW8rGCwqYXEd-EmZy6KuHS74J4rMrRuiXk2mF09dVPUb0Ik4UqXp8dyY3DVpUca5rRMe1CTvBW2JKyqTgrmqUWygnRLeTny9oEHqU69JO4Uw==
    [error_description] => The request is missing a required parameter : code
    [error] => invalid_request
    [request_id] => ea1c4217-5d77-4187-9aff-aec8f357d938
)