Fatal error: Uncaught Error: Interface "GuzzleHttp\Promise\PromisorInterface" not found in /home/rcmch/test.m-s-i.ch/vendor/guzzlehttp/guzzle/src/Pool.php:24 Stack trace: #0 {main} thrown in /home/rcmch/test.m-s-i.ch/vendor/guzzlehttp/guzzle/src/Pool.php on line 24