Fatal error: Uncaught Error: Interface "GuzzleHttp\Promise\PromiseInterface" not found in /home/slsiluser/public_html/service-portal-mobile-responsive/vendor/guzzlehttp/promises/src/Promise.php:14 Stack trace: #0 {main} thrown in /home/slsiluser/public_html/service-portal-mobile-responsive/vendor/guzzlehttp/promises/src/Promise.php on line 14