fud on "[Plugin: Force Login] Custom Login Url with plain permalink format"

Hello,

I am having troubles getting the custom login url to work. This is what I have so far:

//Custom Login URL
function my_login_page( $login_url, $redirect ) {
retu site_url( '/?page_id=2487');
}
add_filter( 'login_url', 'my_login_page', 10, 2 );

For some reason, when the question mark is after the slash, Force Login seems to break. When the question mark is not there, so it looks like :

retu site_url( '/page_id=2487');

Force login will try to direct me to this url : mydomain.com/page_id=2487, which doesn't work.

Thanks!

https://wordpress.org/plugins/wp-force-login/