wp-login.php – 404 error

Hello.
I can only get to the login page (wp-login.php / wp-admin / wp-register) pages from my pc at home.
If I try to get there from another pc or device, I get a 404 page).
I already disabled plugins, tried reverting to the default theme, but no luck.
The site is a working site (an escape room with a vcita premium booking system) and I can not take it offline otherwise clients can not book the rooms.
Please assist.