If your Word Press site goes down and nothing shows up.  It might be a matter of removing all of the plug ins.  To do that, follow these directions:

1. Open an FTP client
2. Navigate to wp-content
3. Locate plugin’s
4. Rename Plugin’s to (Plugin.old)
5. Then try the site and it should open up
6. The site should open now and you can re-activate the plug-ins

Site for more info:
http://www.wpbeginner.com/plugins/how-to-deactivate-all-plugins-when-not-able-to-access-wp-admin/