php - lumen http error 500 in nginx and how to see error

my php project lumen ok on computer wamp (windows.apache.mysql.php) environment.

but when upload server on lnmp (linux,nginx,mysql,php) environment,

i enter url , came http error 500

the root

/home/wwwroot/www.projectname.cn/projectname/public;

so put test.php @ "/home/wwwroot/www.projectname.cn/projectname/public"

enter www.projectname.cn/test.php

it's right page.

so change index.php

<?php $app = require __dir__.'/../bootstrap/app.php'; dump($app); //$app->run();

also http error 500

and @ local environment , add route in projectname/app/http/routes.php

<?php $app->get('/', function() use ($app) {     return $app->welcome(); });  $app->get('/hello', function() {     return "hello "; });

i enter “www.projectname.cn/hello” doesn't work

the routes.php doesn't work

what's maybe reason caused ??

you can see error log dynamically using command

tail -f /var/log/nginx/error.log

this default nginx configuration in debian/ubuntu, have change error.log route.

If cop