WP-Admin not reachable

Looks like the error persists in the frontend. You think that the admin side is cached, but on the contrary, the front side is cached. You don’t see errors on your homepage because it’s cached. But all your pages are giving error. So you have to make sure you remove the correct code. Maybe you couldn’t update properly via ftp.

Add any query to bypass cache on the front:
https://www.institute4languages.com/?asd

error code: 523