Weird Laravel Error gives me 521 HTTP

Here's the whole log stacktrace:

[2018-04-30 12:33:51] local.ERROR: The process has been signaled with signal "2". {"exception":"[object] (Symfony\Component\Process\Exception\RuntimeException(code: 0): The process has been signaled with signal \"2\". at /var/www/vendor/symfony/process/Process.php:392)
[stacktrace]
#0 /var/www/vendor/symfony/process/Process.php(201): Symfony\Component\Process\Process->wait()
#1 /var/www/vendor/laravel/framework/src/Illuminate/Queue/Listener.php(193): Symfony\Component\Process\Process->run(Object(Closure))
#2 /var/www/vendor/laravel/framework/src/Illuminate/Queue/Listener.php(115): Illuminate\Queue\Listener->runProcess(Object(Symfony\Component\Process\Process), '128')
#3 /var/www/vendor/laravel/framework/src/Illuminate/Queue/Console/ListenCommand.php(68): Illuminate\Queue\Listener->listen(NULL, 'sqs', Object(Illuminate\Queue\ListenerOptions))
#4 [internal function]: Illuminate\Queue\Console\ListenCommand->handle()
#5 /var/www/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(29): call_user_func_array(Array, Array)
#6 /var/www/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(87): Illuminate\Container\BoundMethod::Illuminate\Container\{closure}()
#7 /var/www/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(31): Illuminate\Container\BoundMethod::callBoundMethod(Object(Illuminate\Foundation\Application), Array, Object(Closure))
#8 /var/www/vendor/laravel/framework/src/Illuminate/Container/Container.php(564): Illuminate\Container\BoundMethod::call(Object(Illuminate\Foundation\Application), Array, Array, NULL)
#9 /var/www/vendor/laravel/framework/src/Illuminate/Console/Command.php(183): Illuminate\Container\Container->call(Array)
#10 /var/www/vendor/symfony/console/Command/Command.php(252): Illuminate\Console\Command->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Illuminate\Console\OutputStyle))
#11 /var/www/vendor/laravel/framework/src/Illuminate/Console/Command.php(170): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Illuminate\Console\OutputStyle))
#12 /var/www/vendor/symfony/console/Application.php(865): Illuminate\Console\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#13 /var/www/vendor/symfony/console/Application.php(241): Symfony\Component\Console\Application->doRunCommand(Object(Illuminate\Queue\Console\ListenCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#14 /var/www/vendor/symfony/console/Application.php(143): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#15 /var/www/vendor/laravel/framework/src/Illuminate/Console/Application.php(88): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#16 /var/www/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(122): Illuminate\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#17 /var/www/artisan(37): Illuminate\Foundation\Console\Kernel->handle(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#18 {main}
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If you installed a package, did you dumpautoload? What code caused this error? Could a server be down?

The last package I installed was Symfony/Process. Yes I did dump autoload

As the error indicates, you have an error with your queues/job/event classes.

@Robstar haven't changed anything related to my queue/job/event classes.

Try this:

• First backup your vendor folder to be safe
• delete the entire vendor folder
• run composer clearcache
• run composer selfupdate
• run composer update

Try it, if that don't work you many have to

• composer install

Sometimes that has a way of fixing things.

@jlrdw The thing is I have two environments. A dev and a prod in docker. The dev runs off the folder while the prod does composer install while building the image. The error I showed happens on the prod image. So this means that composer install creates the error?

Have you checked for any issues on that package: Symfony/Process

So stupid of me @jlrdw. I forgot that I put a tail -f storage/logs/laravel.log when starting my server to show me the last 10 lines from the error logs. It had nothing to do with Symfony/Process or anything like that.