Fatal error: Uncaught Error: Interface "GuzzleHttp\Promise\PromiseInterface" not found in /home/qld/public_html/tube1/Update Guide/v3.1/assets/libs/payfastSDK/vendor/guzzlehttp/promises/src/RejectedPromise.php:15 Stack trace: #0 {main} thrown in /home/qld/public_html/tube1/Update Guide/v3.1/assets/libs/payfastSDK/vendor/guzzlehttp/promises/src/RejectedPromise.php on line 15