Help Please, can’t access to Appearance – Menus / Customize

Hello guys.
I need a help.
Without any change from my side , few days ago I saw in the dashboard that I’m no longer anymore access to:
Appearance – Menus
Appearance – Customize
When i trying to click on button there comes message:

“This page isn’t working
teatri.ge is currently unable to handle this request.
HTTP ERROR 500”

I already tried:
1. Reinstall WordPress (from ftp)
2. Off all the Plugins
3. change Theme to the default

But nothing helps… ??

The page I need help with: [log in to see the link]