Fatal error: Uncaught Error: Interface "Slim\Psr7\Interfaces\HeadersInterface" not found in /Users/ppss/Sites/PPSS/api/vendor/slim/psr7/src/Headers.php:29 Stack trace: #0 {main} thrown in /Users/ppss/Sites/PPSS/api/vendor/slim/psr7/src/Headers.php on line 29