Admin Blank White Page!!!

Help!!

when I try to login to the admin panel the page is just blank..

https://www.simonmitas.com – is my site

https://www.simonmitas.com/wp-admin/ – is blank

I have changed the plugins folder name in the ftp but still no luck.

I have searched online but cant figure out what else I could do to fix..

The client is waiting for a change on their site ??