While working on a Laravel project i got the error How to fix ReflectionException: Class ClassName Not Found. 
After creating a controller through command line you may face this type of issue.In my case after creating a new controller named UserController I faced this issue like class app\controllers\UserController Not found . Then I found the solution.

So if you are facing this issue try the following 3 commands in terminal/cmd.
Step1. Go to your laravel project directory in cmd.
            cd Applications/MAMP/bin/htdocs/laravel
            Here laravel is my project name.
Step 2: composer update 

Step3: composer dump-autoload

Now access your controller. The bug will fix.

I hope this post will help you a lot. Happy Coding!