Fatal error: Uncaught Error: Interface 'React\Promise\PromiseInterface' not found in /var/www/html/simplesamlphp/vendor/react/promise/src/Internal/FulfilledPromise.php:14
Stack trace:
#0 {main}
  thrown in /var/www/html/simplesamlphp/vendor/react/promise/src/Internal/FulfilledPromise.php on line 14