Website not working / Dashboard not loading

My website will not load and I can’t access the dashboard. I am getting this error message when I try to go to the dashboard: Safari can’t open the page “http://terristefanko.com/wp-admin/” because Safari can’t establish a connection to the server “terristefanko.com” . I get an error when I use different browsers too (Google Chrome, Firefox, Internet Explorer). When I try viewing my website, I get this error: Error 500 – Internal Server Error; An error was encountered while processing your request. Typically this is a temporary condition. Please contact the web site owner for further assistance.

The blog I need help with is terristefanko.com.

I went through my InMotion and reset plugins using phpMyAdmin to “a:0:{}” and this did not help.