Fatal error: Uncaught Error: Interface 'GuzzleHttp\Promise\PromisorInterface' not found in C:\inetpub\wwwroot\mantis\vendor\guzzlehttp\guzzle\src\Pool.php:20 Stack trace: #0 {main} thrown in C:\inetpub\wwwroot\mantis\vendor\guzzlehttp\guzzle\src\Pool.php on line 20