Problems with wordpress plugins with plugins on AWS

I have installed wordpress on AWS using this tuto :

http://ift.tt/1Tpd9hq

I had problems with ftp access so I changed the /var/www/projectname rep to 777 and it's solved.

Now I finding problems when working withs plugins. For exemple when I added plugins for sliders, after adding images they don't show on the website page (onlways loading).

Do you have any ideas for the wordpress plugins issues on the AWS? Maybe something with the mysql database?

THank you for you help :)

via Chebli Mohamed