Fatal error: Uncaught Error: Interface "GuzzleHttp\Promise\PromisorInterface" not found in C:\Servers\htdocs\inventory.fitzalan.co.uk\vendor\guzzlehttp\guzzle\src\Pool.php:24 Stack trace: #0 {main} thrown in C:\Servers\htdocs\inventory.fitzalan.co.uk\vendor\guzzlehttp\guzzle\src\Pool.php on line 24