Slim Application Error

The application could not run because of the following error:
Details

Type: Odan\Session\Exception\SessionException
Code: 0
Message: Failed to start the session because headers have already been sent by "/app/config/Parameters.php" at line 17.
File: /app/vendor/odan/session/src/PhpSession.php
Line: 55
Trace

#0 /app/vendor/odan/session/src/Middleware/SessionMiddleware.php(42): Odan\Session\PhpSession->start()
#1 /app/vendor/slim/slim/Slim/MiddlewareDispatcher.php(168): Odan\Session\Middleware\SessionMiddleware->process(Object(Slim\Psr7\Request), Object(Psr\Http\Server\RequestHandlerInterface@anonymous))
#2 /app/app/Http/Middleware/AnalyticsEventsFlushMiddleware.php(24): Psr\Http\Server\RequestHandlerInterface@anonymous->handle(Object(Slim\Psr7\Request))
#3 /app/vendor/slim/slim/Slim/MiddlewareDispatcher.php(168): SuperCity\App\Http\Middleware\AnalyticsEventsFlushMiddleware->process(Object(Slim\Psr7\Request), Object(Psr\Http\Server\RequestHandlerInterface@anonymous))
#4 /app/app/Http/Middleware/AuthenticationMiddleware.php(42): Psr\Http\Server\RequestHandlerInterface@anonymous->handle(Object(Slim\Psr7\Request))
#5 /app/vendor/slim/slim/Slim/MiddlewareDispatcher.php(168): SuperCity\App\Http\Middleware\AuthenticationMiddleware->process(Object(Slim\Psr7\Request), Object(Psr\Http\Server\RequestHandlerInterface@anonymous))
#6 /app/app/Http/Middleware/StandCheckMiddleware.php(27): Psr\Http\Server\RequestHandlerInterface@anonymous->handle(Object(Slim\Psr7\Request))
#7 /app/vendor/slim/slim/Slim/MiddlewareDispatcher.php(168): SuperCity\App\Http\Middleware\StandCheckMiddleware->process(Object(Slim\Psr7\Request), Object(Psr\Http\Server\RequestHandlerInterface@anonymous))
#8 /app/app/Http/Middleware/RequestStackMiddleware.php(26): Psr\Http\Server\RequestHandlerInterface@anonymous->handle(Object(Slim\Psr7\Request))
#9 /app/vendor/slim/slim/Slim/MiddlewareDispatcher.php(168): SuperCity\App\Http\Middleware\RequestStackMiddleware->process(Object(Slim\Psr7\Request), Object(Psr\Http\Server\RequestHandlerInterface@anonymous))
#10 /app/app/Http/Middleware/EndpointHandleTimeMiddleware.php(42): Psr\Http\Server\RequestHandlerInterface@anonymous->handle(Object(Slim\Psr7\Request))
#11 /app/vendor/slim/slim/Slim/MiddlewareDispatcher.php(121): SuperCity\App\Http\Middleware\EndpointHandleTimeMiddleware->process(Object(Slim\Psr7\Request), Object(Psr\Http\Server\RequestHandlerInterface@anonymous))
#12 /app/vendor/slim/slim/Slim/Middleware/ErrorMiddleware.php(76): Psr\Http\Server\RequestHandlerInterface@anonymous->handle(Object(Slim\Psr7\Request))
#13 /app/vendor/slim/slim/Slim/MiddlewareDispatcher.php(121): Slim\Middleware\ErrorMiddleware->process(Object(Slim\Psr7\Request), Object(Psr\Http\Server\RequestHandlerInterface@anonymous))
#14 /app/app/AppPortal/Http/Middleware/AddContentSecurityPolicyMiddleware.php(16): Psr\Http\Server\RequestHandlerInterface@anonymous->handle(Object(Slim\Psr7\Request))
#15 /app/vendor/slim/slim/Slim/MiddlewareDispatcher.php(168): SuperCity\App\AppPortal\Http\Middleware\AddContentSecurityPolicyMiddleware->process(Object(Slim\Psr7\Request), Object(Psr\Http\Server\RequestHandlerInterface@anonymous))
#16 /app/vendor/slim/slim/Slim/Middleware/BodyParsingMiddleware.php(64): Psr\Http\Server\RequestHandlerInterface@anonymous->handle(Object(Slim\Psr7\Request))
#17 /app/vendor/slim/slim/Slim/MiddlewareDispatcher.php(121): Slim\Middleware\BodyParsingMiddleware->process(Object(Slim\Psr7\Request), Object(Psr\Http\Server\RequestHandlerInterface@anonymous))
#18 /app/vendor/slim/slim/Slim/MiddlewareDispatcher.php(65): Psr\Http\Server\RequestHandlerInterface@anonymous->handle(Object(Slim\Psr7\Request))
#19 /app/vendor/slim/slim/Slim/App.php(199): Slim\MiddlewareDispatcher->handle(Object(Slim\Psr7\Request))
#20 /app/vendor/slim/slim/Slim/App.php(183): Slim\App->handle(Object(Slim\Psr7\Request))
#21 /app/www/app_portal_index.php(116): Slim\App->run()
#22 {main}