Fatal error: Uncaught Error: Interface "GuzzleHttp\Promise\PromiseInterface" not found in /home/alumni/slicks/iswc/vendor/guzzlehttp/promises/src/RejectedPromise.php:15 Stack trace: #0 {main} thrown in /home/alumni/slicks/iswc/vendor/guzzlehttp/promises/src/RejectedPromise.php on line 15