使用LEMP堆栈和php7.1的laravel日志错误

Question

嗨，我正在尝试使用LEMP堆栈php 7.1将laravel 5.6应用程序上传到VPS.am，这是我在运行以下命令后进入laravel.log的错误

nano storage/logs/laravel.log

[2018-07-11 11:57:26] production.ERROR: syntax error, unexpected '?', 
expecting variable (T_VARIABLE) {"exception":"[object] 
(Symfony\\Component\\Debug\\Exception\\Fat$[stacktrace]
#0 /var/www/laravel/vendor/composer/ClassLoader.php(322): 
Composer\\Autoload\\includeFile('/var/www/larave...')
#1 [internal function]: Composer\\Autoload\\ClassLoader- 
>loadClass('Symfony\\\\Compone...')

如果这很相关，我怀疑我的问题在下面的文件中

sudo nano sites-available/default

location / {
# First attempt to serve request as file, then
# as directory, then fall back to displaying a 404.
try_files $uri $uri/ /index.php$is_args$args;
}

# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
location ~ \.php$ {
include snippets/fastcgi-php.conf;
#
#       # With php7.0-cgi alone:
#       fastcgi_pass 127.0.0.1:9000;
#       # With php7.0-fpm:
fastcgi_pass unix:/run/php/php7.1-fpm.sock;
}

很抱歉，这是一个愚蠢的问题..我对此很陌生