500 error on my site

I have just added your plugin of the WP Fastest Cache plugin onto my wordpress website, which is I-MAX theme updated to wordpress version 4.7. I have checked the normal stuff to try to cache, and now it totally crashed my website. I am receiving a 500 internal error. I tried to go to admin, but receiving a 500 internal error. I tried turing the .htacess to backup and then deleting original file. Still error. I tried going into the plugins and deleting the plugin. Still error. I tried renaming the plugins folder … Still error. It is not the wp theme, so for some way or another, your plugin is stuck on my website and crashing. Please I need your help.