Fatal error: Uncaught Error: Interface "GuzzleHttp\Promise\PromiseInterface" not found in C:\Servers\htdocs\inventory.fitzalan.co.uk\vendor\guzzlehttp\promises\src\FulfilledPromise.php:15 Stack trace: #0 {main} thrown in C:\Servers\htdocs\inventory.fitzalan.co.uk\vendor\guzzlehttp\promises\src\FulfilledPromise.php on line 15