app\Http\Kernel.php

<?php
// ...
	protected $middleware = [
		// ...
		'App\Http\Middleware\ValidProxies',
	];
// ...

app\Http\Middleware\ValidProxies.php

<?php namespace App\Http\Middleware;

use Closure;

class ValidProxies {

	/**
	 * Handle an incoming request.
	 *
	 * @param  \Illuminate\Http\Request  $request
	 * @param  \Closure  $next
	 * @return mixed
	 */
	public function handle($request, Closure $next)
	{
		// Proxies
		$request->setTrustedProxies([ $request->getClientIp() ]);

		return $next($request);
	}
}

Fixes various issues with Laravel sitting behind a load balancer / firewall which accepts HTTPS requests and forward them to the Laravel Web Server on port 80. Essentially, this function tells Laravel to trust the X-Forwarded headers sent by the load balancer.