Fatal error: Uncaught GuzzleHttp\Exception\ClientException: Client error: `POST https://api.amazon.com/auth/o2/token` resulted in a `401 Unauthorized` response: {"error_description":"Client authentication failed","error":"invalid_client"} in /var/www/html/sp-api/vendor/guzzlehttp/guzzle/src/Exception/RequestException.php:113 Stack trace: #0 /var/www/html/sp-api/vendor/guzzlehttp/guzzle/src/Middleware.php(72): GuzzleHttp\Exception\RequestException::create() #1 /var/www/html/sp-api/vendor/guzzlehttp/promises/src/Promise.php(209): GuzzleHttp\Middleware::GuzzleHttp\{closure}() #2 /var/www/html/sp-api/vendor/guzzlehttp/promises/src/Promise.php(158): GuzzleHttp\Promise\Promise::callHandler() #3 /var/www/html/sp-api/vendor/guzzlehttp/promises/src/TaskQueue.php(52): GuzzleHttp\Promise\Promise::GuzzleHttp\Promise\{closure}() #4 /var/www/html/sp-api/vendor/guzzlehttp/promises/src/Promise.php(251): GuzzleHttp\Promise\TaskQueue->run() #5 /var/www/html/sp-api/vendor/guzzlehttp/promises/src/Promise.php(227): GuzzleHttp\Promise\Promise->invokeWaitFn() #6 /var/www/html/sp-api/vendor/guzzlehttp/promises/src/Promise.php(272): GuzzleHttp\Promise\Promise->waitIfPending() #7 /var/www/html/sp-api/vendor/guzzlehttp/promises/src/Promise.php(229): GuzzleHttp\Promise\Promise->invokeWaitList() #8 /var/www/html/sp-api/vendor/guzzlehttp/promises/src/Promise.php(69): GuzzleHttp\Promise\Promise->waitIfPending() #9 /var/www/html/sp-api/vendor/guzzlehttp/guzzle/src/Client.php(124): GuzzleHttp\Promise\Promise->wait() #10 /var/www/html/sp-api/vendor/jlevers/selling-partner-api/src/Authentication/AbstractAuthenticator.php(44): GuzzleHttp\Client->send() #11 /var/www/html/sp-api/vendor/jlevers/selling-partner-api/src/Authentication/LWAAuthenticator.php(40): SellingPartnerApi\Authentication\AbstractAuthenticator->makeTokenRequest() #12 /var/www/html/sp-api/vendor/jlevers/selling-partner-api/src/Authentication/AbstractAuthenticator.php(30): SellingPartnerApi\Authentication\LWAAuthenticator->getAccessToken() #13 /var/www/html/sp-api/vendor/saloonphp/saloon/src/Http/PendingRequest/AuthenticatePendingRequest.php(20): SellingPartnerApi\Authentication\AbstractAuthenticator->set() #14 /var/www/html/sp-api/vendor/saloonphp/saloon/src/Http/PendingRequest.php(306): Saloon\Http\PendingRequest\AuthenticatePendingRequest->__invoke() #15 /var/www/html/sp-api/vendor/saloonphp/saloon/src/Http/PendingRequest.php(114): Saloon\Http\PendingRequest->tap() #16 /var/www/html/sp-api/vendor/saloonphp/saloon/src/Traits/Connector/SendsRequests.php(176): Saloon\Http\PendingRequest->__construct() #17 /var/www/html/sp-api/vendor/saloonphp/saloon/src/Traits/Connector/SendsRequests.php(65): Saloon\Http\Connector->createPendingRequest() #18 /var/www/html/sp-api/vendor/jlevers/selling-partner-api/src/Seller/FeedsV20210630/Api.php(78): Saloon\Http\Connector->send() #19 /var/www/html/sp-api/index.php(176): SellingPartnerApi\Seller\FeedsV20210630\Api->createFeedDocument() #20 {main} thrown in /var/www/html/sp-api/vendor/guzzlehttp/guzzle/src/Exception/RequestException.php on line 113