Website doesn't work after changing folder name in public_html cpanel

I have a website running. I put all the files of my laravel5.2 project in public_html of the cpanel, say A. Everything is working fine with url:
www.mydomain.com/A

I need to update something, so I had another folder inside public_html say B, and B is for testing purpose, and I access it through www.mydomain.com/B

I completed my testing, everything is working fine on testing. Testing has separate database.

Now I want to make it real live website so, I changed the name of my testing B to A.
This is what changes I made. 1. updated .env files copied all the content from A to B because I want to use live one's database.
One thing I doubt about APP KEY, tell me If I need to generate new one.

After doing all this, I have a strange problem now.

When I change my testing B to live A, it doesnt' work properly. I am able to login, but see nothing, means I don't see actual data coming from database just templates text, on admin panel.
But If I change folder B to anything else everything works well.

Please help me, what am I missing?

via Chebli Mohamed