Fatal error: Uncaught Error: Interface 'React\Promise\PromiseInterface' not found in /home/soh-works/www/websoket-sample/vendor/react/promise/src/CancellablePromiseInterface.php:5 Stack trace: #0 {main} thrown in /home/soh-works/www/websoket-sample/vendor/react/promise/src/CancellablePromiseInterface.php on line 5