Locked out of wp-admin

You mean that you can’t go to wp-admin/ directory ? That should never happen.

Yeah, my website is https://wantrid.com and to get into the backend I go to https://wantrid.com/wp-admin (as all WP sites have /wp-admin)

When I activate maintenance mode and try to go to https://wantrid.com/wp-admin I get the maintenance page instead of the admin login page. You can try now as I have my site in maintenance mode now.

The problem is that you have a redirection to a custom login page, in this case you will have to edit the file functions.php to add an exception, or simply use the standard wp-admin page.