See the guide I posted on this link https://laracasts.com/discuss/channels/laravel/error-on-site-when-upload-on-live-server-errorexception-in-classloaderphp-line-444 I was so mad that I actually downloaded using composer and installed a laravel 5.4 got it working, then uploaded it to my host and it works perfect.
This question is asked and answered at least 5 to 10 times weekly it seems like.
Just follow the guide exactly. Prior to that post that ticked me off I had always used 5.1. I went through all that just to prove a point that if you follow the guide it really really works.