Does a real bad code can cause 502 error?

@EliyaCohen Have you checked that laravel logfile? Have you installed composer packages? Is the storage folder writeable? Have you created an .env file?

@renedekat Done Done Done, and nothin unusual.

@EliyaCohen Have you checked the web server logs? Make sure they're enabled though.

Also check this: http://stackoverflow.com/questions/21288475/getting-502-setting-up-laravel-4-on-nginx-machine

@renedekat When I try to access the nginx log I get permission denied.. dunno how to fix this. Regarding to the post, I don't think it's useful for me :\

This is my nginx.conf:

server {
    listen 80 default_server;
    server_name default;
    root /home/forge/default/public;

    # FORGE SSL (DO NOT REMOVE!)
    # ssl_certificate;
    # ssl_certificate_key;

    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;

    index index.html index.htm index.php;

    charset utf-8;

    location / {
        try_files $uri $uri/ /index.php?$query_string;
    }

    location = /favicon.ico { access_log off; log_not_found off; }
    location = /robots.txt  { access_log off; log_not_found off; }

    access_log off;
    error_log  /var/log/nginx/default-error.log error;

    error_page 404 /index.php;

    location ~ \.php$ {
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
    }

    location ~ /\.ht {
        deny all;
    }
}

Update

Got an errorlog in laravel.log:

  GNU nano 2.2.6                                                   File: laravel.log

[2016-02-03 23:14:29] production.ERROR: UnexpectedValueException: Invalid Host "%s" in /home/forge/default/vendor/symfony/http-foundation/Request.php:1225
Stack trace:
#0 /home/forge/default/vendor/symfony/http-foundation/Request.php(1034): Symfony\Component\HttpFoundation\Request->getHost()
#1 /home/forge/default/vendor/symfony/http-foundation/Request.php(1064): Symfony\Component\HttpFoundation\Request->getHttpHost()
#2 /home/forge/default/vendor/symfony/http-foundation/Request.php(1698): Symfony\Component\HttpFoundation\Request->getSchemeAndHttpHost()
#3 /home/forge/default/vendor/symfony/http-foundation/Request.php(1048): Symfony\Component\HttpFoundation\Request->prepareRequestUri()
#4 /home/forge/default/vendor/symfony/http-foundation/Request.php(1750): Symfony\Component\HttpFoundation\Request->getRequestUri()
#5 /home/forge/default/vendor/symfony/http-foundation/Request.php(926): Symfony\Component\HttpFoundation\Request->prepareBaseUrl()
#6 /home/forge/default/vendor/symfony/http-foundation/Request.php(1816): Symfony\Component\HttpFoundation\Request->getBaseUrl()
#7 /home/forge/default/vendor/symfony/http-foundation/Request.php(886): Symfony\Component\HttpFoundation\Request->preparePathInfo()
#8 /home/forge/default/vendor/laravel/framework/src/Illuminate/Http/Request.php(108): Symfony\Component\HttpFoundation\Request->getPathInfo()
#9 /home/forge/default/vendor/laravel/framework/src/Illuminate/Routing/Matching/UriValidator.php(19): Illuminate\Http\Request->path()
#10 /home/forge/default/vendor/laravel/framework/src/Illuminate/Routing/Route.php(222): Illuminate\Routing\Matching\UriValidator->matches(Object(Illuminate\Routing\Route), Object(Illuminate\H$
#11 /home/forge/default/vendor/laravel/framework/src/Illuminate/Routing/RouteCollection.php(233): Illuminate\Routing\Route->matches(Object(Illuminate\Http\Request), true)
#12 [internal function]: Illuminate\Routing\RouteCollection->Illuminate\Routing\{closure}('info', Object(Illuminate\Routing\Route))
#13 /home/forge/default/vendor/laravel/framework/src/Illuminate/Support/Arr.php(153): call_user_func(Object(Closure), 'info', Object(Illuminate\Routing\Route))
#14 /home/forge/default/vendor/laravel/framework/src/Illuminate/Routing/RouteCollection.php(234): Illuminate\Support\Arr::first(Array, Object(Closure))
#15 /home/forge/default/vendor/laravel/framework/src/Illuminate/Routing/RouteCollection.php(146): Illuminate\Routing\RouteCollection->check(Array, Object(Illuminate\Http\Request))
#16 /home/forge/default/vendor/laravel/framework/src/Illuminate/Routing/Router.php(750): Illuminate\Routing\RouteCollection->match(Object(Illuminate\Http\Request))
#17 /home/forge/default/vendor/laravel/framework/src/Illuminate/Routing/Router.php(659): Illuminate\Routing\Router->findRoute(Object(Illuminate\Http\Request))
#18 /home/forge/default/vendor/laravel/framework/src/Illuminate/Routing/Router.php(635): Illuminate\Routing\Router->dispatchToRoute(Object(Illuminate\Http\Request))
#19 /home/forge/default/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(236): Illuminate\Routing\Router->dispatch(Object(Illuminate\Http\Request))
#20 [internal function]: Illuminate\Foundation\Http\Kernel->Illuminate\Foundation\Http\{closure}(Object(Illuminate\Http\Request))
#21 /home/forge/default/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(139): call_user_func(Object(Closure), Object(Illuminate\Http\Request))
#22 /home/forge/default/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/VerifyCsrfToken.php(50): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illumina$
#23 [internal function]: Illuminate\Foundation\Http\Middleware\VerifyCsrfToken->handle(Object(Illuminate\Http\Request), Object(Closure))
#24 /home/forge/default/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(124): call_user_func_array(Array, Array)
#25 /home/forge/default/vendor/laravel/framework/src/Illuminate/View/Middleware/ShareErrorsFromSession.php(49): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\H$
#26 [internal function]: Illuminate\View\Middleware\ShareErrorsFromSession->handle(Object(Illuminate\Http\Request), Object(Closure))
#27 /home/forge/default/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(124): call_user_func_array(Array, Array)
#28 /home/forge/default/vendor/laravel/framework/src/Illuminate/Session/Middleware/StartSession.php(62): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Req$
#29 [internal function]: Illuminate\Session\Middleware\StartSession->handle(Object(Illuminate\Http\Request), Object(Closure))
#30 /home/forge/default/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(124): call_user_func_array(Array, Array)
#31 /home/forge/default/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/AddQueuedCookiesToResponse.php(37): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illumi$
#32 [internal function]: Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse->handle(Object(Illuminate\Http\Request), Object(Closure))
#33 /home/forge/default/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(124): call_user_func_array(Array, Array)
#34 /home/forge/default/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/EncryptCookies.php(59): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Re$
#35 [internal function]: Illuminate\Cookie\Middleware\EncryptCookies->handle(Object(Illuminate\Http\Request), Object(Closure))
#36 /home/forge/default/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(124): call_user_func_array(Array, Array)
#37 /home/forge/default/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/CheckForMaintenanceMode.php(44): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object($
#38 [internal function]: Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode->handle(Object(Illuminate\Http\Request), Object(Closure))
#39 /home/forge/default/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(124): call_user_func_array(Array, Array)
#40 [internal function]: Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#41 /home/forge/default/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(102): call_user_func(Object(Closure), Object(Illuminate\Http\Request))
#42 /home/forge/default/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(122): Illuminate\Pipeline\Pipeline->then(Object(Closure))
#43 /home/forge/default/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(87): Illuminate\Foundation\Http\Kernel->sendRequestThroughRouter(Object(Illuminate\Http\Request))
#44 /home/forge/default/public/index.php(53): Illuminate\Foundation\Http\Kernel->handle(Object(Illuminate\Http\Request))
#45 {main}

I get this error in my default-error.log over and over:

2016/02/04 14:57:28 [error] 1044#1044: *7248 connect() to unix:/var/run/php/php7.0-fpm.sock failed (11: Resource temporarily unavailable) while connecting to upstream, client: 123.456.78.90, server: default, request: "GET / HTTP/1.1", upstream: "fastcgi://unix:/var/run/php/php7.0-fpm.sock:", host: "domain.com"

Any update on this issue? @EllyaCohen

Yes. 1 thing I forgot to mention, is that my phone version was 7.0.0 and used sockets. Because of too many connections, the socket couldn't handle it and crushed, which lead to 502 error.

Then yes. An unefficient code may lead to 502 error.